CHAPTER 47 DEMESTIK VENTILATION A Lesson from the Cold Pits We require in our houses an artificial temperate climate, which shall be uniform throughout. And at the same time we need a gentle movement of air that shall supply the requirements of respiration, without any gusts or drafts or alternations of temperature. Everybody will admit that these are fundamental desiderata, but whoever does so becomes thereby a denouncer of open great fireplaces and of every system of heating, which is dependent on any kind of stoves with fuel burning in the rooms that are to be inhabited. All such devices concentrate the heat in one part of each room and demand the admission of cold air for some other part or parts, thereby violating the primary condition of uniform temperature. The usual preceding effects especially outrageous violation of this, as I showed in the last chapter. I might have added domestic cleanliness among the desiderata. But in the matter of fireplaces, the true-born Britain, in spite of his fastidiousness in respect to shirt collars, etc., is a devoted worshipper of dirt.  It is evident that in order to completely fulfill the first named requirements, we must, in winter, supply our model residents with fresh, artificially warmed air, and in summer with fresh, cool air. How is this to be done? An approach to a practical solution is afforded by examining what is actually done under circumstances where the ventilation problem presents the greatest possible difficulties, and where, nevertheless, these difficulties have been effectually overcome. Such a case is presented by a deep coal mine. Here we have a little working world, inhabited by men and horses, deep in the bowels of the earth, far away from the air that must be supplied in sufficient quantities, not only to overcome the vitiation due to their own breathing, but also to sweep out the deadly gaseous emanations from the coal itself. Imagine your dwelling house buried a quarter of a mile of perpendicular depth below the surface of the earth, and its walls giving off suffocating and explosive gases in such quantities that steady and abundant ventilation shall be a matter of life or death. And that in spite of this, it is made so far habitable that men who spend half their days there retain robust health and live to green old age, and that horses, after remaining their day and night for many months, actually improve in condition. Imagine further that the house thus ventilated has some hundreds of small, very low-ruffed rooms, and a system of passages or corridors within a united length of many miles, and that its inhabitants count by the hundreds. Such dwellings being thus ventilated and rendered habitable for men and beast, it is idle to dispute the practical possibility of supplying fresh air of any given temperature to a mere box of brick or stone, standing in the midst of the atmosphere, and containing but a few passages and apartments. The problem is solved in the coal pit by simply and skillfully controlling and directing the natural movements of unequally hated volumes of air, complex mechanical devices for forcing the ventilation by means of gigantic fan wheels, etc., or by steam jets have been tried and are now generally abandoned. An inlet and an outlet are provided, and no air is allowed to pass inward or outward by any other course than that which has been prearranged for the purposes of efficient ventilation. I place special emphasis on this condition, believing that its systematic violation is the primary cause of the bungling muddle of our domestic ventilation. Let us suppose that we're going to open a coal pit to mine coal on a certain estate. We first ascertain the dip of the seam, or its deviation from horizontality, and then start at the lowest part, not as some suppose, at that part nearest to the surface. The reason for this is obvious on a little reflection, for if we began at the shallowest part of an ordinary water bearing stratum, we should have to drive down under water. But by beginning at the lowest part and driving upwards, we can at once form a sump, or bottom receptacle, to receive the drainage and from which the accumulated water may be pumped. This, however, is only by the way and not directly connected with our main subject, the ventilation. In order to secure this, the modern practice is to sink two pits, a pair, as they are called, side by side at any convenient distance from each other. If they are deep, it becomes necessary to commence ventilation of the mere shafts themselves in the course of sinking. This is done by driving an airway, a horizontal tunnel from one to the other, and then establishing an upcast in one of them by simply lighting a fire there. This destroys the balance between the two communicating columns of air. The cooler column in the shaft without a fire, being heavier, falls against the lighter column and pushes it up, just as the air is pushed up one leg of a U-tube when we pour water down the other. Even in this preliminary work, if the pits are so deep that more than one airway is driven, it is necessary to stop the upper ways and leave only the lowest open in order that the ventilation shall not take a short and useless cut as it does up our fireplace openings. Let us now suppose that the pair of pits are sunk down to the seam with a further extension below to form the water sump. There are two chief modes of working a coal seam, the pillar install and the long wall, or more modern system. For present illustration, I select the latter as the simplest in respect to ventilation. This method, as ordinarily worked, consists essentially in first driving roads through the coal from the pits to the outer boundary of the area to be worked, then cutting a crossroad that shall connect these, thereby exposing a long wall of coal, which in working is gradually cut away towards the pits, the roof remaining behind being allowed to fall in. Let us begin to do this by driving, first of all, two main roads, one from each pit. It is evident that as we proceed in such burrowing, we shall presently find ourselves in a cul-de-sac so far away from the outer air that suffocation is threatened. This will be equally the case with both roads. Let us now drive a cross cut from the end of each main road and thus establish a communication from the downcast shaft through its road, then through the drift to the upcast road and pit. But in order that the air shall take this roundabout course, we must close the direct drift that we previously made between the two shafts, or it will proceed by that shorter and easier course. Now we shall have air throughout both our main roads, and we may drive on further until we are again stopped by approximate suffocation. When this occurs, we make another cross cut. But in order that it may act, we must stop the first one. So we go on until we reach the working, and then the long wall itself becomes the cross communication, and through this working gallery the air sweeps freely and effectually. In the above, I have only considered the simplest possible elements of the problem. The practical coal pit in full working has a multitude of intervening passages and splits, where the main current from the downcast is divided in order to proceed through the various streets and lanes of the subterranean town as may be required. And these divided currents are finally reunited ere they reach the upcast shaft, which casts them all out into the upper air. In a colliery, worked on the pillar install system, i.e. by taking out the coal so as to leave a series of square chambers with pillars of coal in the middle to support the roof, the windings of the air between the multitude of passages is curiously complex. And its absolute obedience to the commands of the mining engineer proves how completely the most difficult problems of ventilation may be solved when ignorance and prejudice are not permitted to bar the progress of the practical applications of simple scientific principles. Here the necessity of closing all false outlets is strikingly demonstrated by the mechanism and working of the stoppings or partitions that close all unrequired openings. The air in many pits has to travel several miles in order to get from the downcast to the upcast shaft, though they may be but a dozen yards apart. Formally the same shaft served both for up and downcast by making a wooden division of Bratice down the middle. This is now prohibited on account of serious accidents that have been caused by the fracture of the Bratice. But it would not do to carry the coal from the workings to the pit by these sinuous air courses. What then is done? A direct road is made for the coal, but if it were left open the air would choose it. This is prevented by an arrangement similar to that of canal locks. Valve doors or stoppings are arranged in pairs, and when the hurryer arrives with his corvée, a pit carriage, one door is opened and the other remaining shut. Then the corvée is hurried into the space between the doors and the entry door is closed. Now the exit door is open, and thus no continuous opening is ever permitted. Only one such opening would derange the ventilation of the whole pit, or of that portion fed by the split thus allowed to escape. It would in fact correspond to the action of our open fireplaces in rendering effective ventilation impossible. The following from the report of the Lord's Committee on Accidents in Coal Mines, 1849, illustrates the magnitude of the ventilation arrangements then at work. In the Hetton Colliery there were two downcast shafts and one upcast. The former, about 12 feet and the latter 14 feet diameter. There were three furnaces at the bottom of the upcast, each about nine feet wide with about four feet length of great bars. The depth of the upcast and one downcast 900 feet, and of the other downcast 1056 feet. The quantity of air introduced by the action of these furnaces was 168,560 cubic feet per minute at a cost of about eight tons of coal per day. The rate of motion of the air was 1097 feet per minute, above 12 miles per hour. This whole current was divided by splitting into 16 currents of about 11,000 cubic feet each per minute, having on an average a course of four and one-quarter miles each. This distance was however very irregular. The greatest length of course being nine and one-tenth miles, total length 70 miles. Thus 168,560 cubic feet of air were driven through these great distances at a rate of 12 miles per hour and a cost of eight tons of coal per day. All these magnitudes are greatly increased in coal mines of the present time. As much as 250,000 cubic feet of air per minute are now passed through the shafts of one mine. The problem of domestic ventilation, as compared with coal pit ventilation, involves an additional requirement, that of warming, but this does not at all increase the difficulty. And I even go so far as to believe that cooling in summer may be added to warming in winter by one and the same ventilating arrangement. As I am not a builder and claim no patent rights, the following must be regarded as a general indication, not as a working specification of my scheme for domestic ventilation and the regulation of home climate. The model house must have an upcast shaft placed as nearly in the middle of the building as possible, with which every room must communicate, either by a direct opening or through a lateral shaft. An ordinary chimney built in the usual manner is all that is required to form such a main shaft. There must be no stoves nor any fireplaces in any room accepting the kitchen, of which anon. All the windows must be made to fit closely, as nearly airtight as possible. No downcast shaft is required, the pressure of the surrounding outer atmosphere being sufficient. Outside of the house or on the ground floor, on the north side, if possible, should be a chamber heated by flus, hot air, steam, a suitable stove, or water pipes, and with one adjustable opening communicating with the outer fresh air, and another on the opposite side connected by a shaft or airway with the hall of the ground floor and the general staircase. Each room to have an opening at its upper part communicating with the chimney, like an or not's ventilator and capable of adjustment as regards area of aperture and other openings of corresponding or excessive combined area leading from the hall or staircase to the lower part of the room. These may be covered with perforated zinc or wire gauze, so that the air may enter in a gentle broken stream. All the outer house doors must be double, i.e., with a porch or vestibule, and only one of each pair of doors opened at once. These should be well fitted, and the staircase airtight. The kitchen to communicate with the rest of the house by similar double doors, and the kitchen fire to communicate directly with the upcast shaft or chimney by as small a stovepipe as practicable. The kitchen fire will thus start the upcast and commence the draft of air from the warm chamber through the house towards the several openings into the shaft. In cold weather, this upcast action will be greatly reinforced and maintained by the general warmth of all the air in the house, which itself will bodily become an upcast shaft immediately the inner temperature exceeds that of the air outside. But the upcast of warm air can only take place by the admission of fresh air through the heating chamber, thence to the hall and staircase, and thence onward through the rooms into the final shaft or chimney, the openings into and out of the rooms being adjustable. They may be so regulated that each shall receive an equal share of fresh warm air. Or, if desired, the bedroom chimney valves may be closed in the daytime, and thus the heat economized by being used only for the dayrooms. Or, vice versa, the communication between the upcast shaft and the lower rooms may be closed in the evening, and thus all the warm air be turned into the bedrooms at bedtime. If the area of the entrance apertures of the rooms exceeds that of the outlet, only the ladder need be adjusted. The room doors may, in fact, be left wide open without any possibility of draft beyond the ventilation current, which is limited by the dimension of the opening from the room into the shaft or chimney. So far, for winter time, when the ventilation problem is the easiest, because then the excess of inner warmth converts the whole house into an upcast shaft, and the whole outer atmosphere becomes a downcast. In the summertime, the kitchen fire would probably be insufficient to secure a sufficiently active upcast. To help this, there should be in one of the upper rooms, say an attic, an opening into the chimney secured by a small, well-fitting door, and altogether enclosed within the chimney a small, automatic, slow combustion stove, of which many were exhibited in South Kensington that require feeding but once in twenty-four hours, or a large gas burner. The heating chamber below must now be converted into a cooling chamber by an arrangement of wet cloths, presently to be described, so that all the air entering the house shall be reduced in temperature. Or the winter course of ventilation may be reversed by building a special shaft connected with the kitchen fire, which in this case must not communicate with the house shaft. This special shaft may thus be made an upcast, and the room supplied with air from above down the house shaft through the rooms and out the kitchen via the winter heating chamber, which now has its communication with the outside air closed. Reverting to the first name method, which I think is better than the second, besides being less expensive, I must say a few concluding words on an important supplementary advantage, which is obtainable wherever all the air entering the house passes through one opening, completely under control, like that of our heating chamber. The great evil of our town atmosphere is its dirtiness. In the winter it is polluted with soot particles. In the dry summer weather the traffic and the wind stir up and mix with it particles of dust, having a composition that is better ignored when we consider to the quantity of horse dung that is dried and pulverized on our roadways. All the dust that falls on our books and furniture was first suspended in the air we breathe inside our rooms. Can we get rid of any practically important portion of this? I am able to answer this question not merely on theoretical grounds, but as a result of practical experiments described in the following chapter, in which is reprinted a paper I read at the Society of Arts, March 19, 1879, recommending the enclosure of London backyards with a roofing of wall canvas or paper hangers canvas, so as to form cheap conservatories. This canvas, which costs about three pence per square yard, is a kind of coarse, strong, fluffy gauze, emitting light and air, but acting very effectively as an air filter by catching and stopping the particles of soot and dust that are so fatal to urban vegetation. I propose, therefore, that this well-tried device should be applied at the entrance aperture of our heating chamber, that the screens shall be well wetted in the summer in order to obtain the cooling effect of evaporation, and in the winter shall be either wet or dry, as may be found desirable. The Parliament House experiments prove that they are good filters when wetted, and mine that they act similarly when dry. By thus applying the principles of colliery ventilation to a specially constructed house, we may, I believe, obtain a perfectly controllable indoor climate with a range of variation not exceeding four or five degrees between the warmest and the coldest part of the house, or eight or nine degrees between summer and winter, and this may be combined with an abundant supply of fresh air everywhere, all filtered from the grosser portions of its irritant dust which is positively poisonous to delicate lungs and damaging to all. The cost of fuel would be far less than with existing arrangements, and the labor of attending to one or two fires and the valves would also be less than that now required in the carrying of coal scuttles, the removal of ashes, the cleaning of fireplaces, and the curtains and furniture they befall by their escaping dust and smoke. It is obvious that such a system of ventilation may even be applied to existing houses by mending the ill-fitting windows, shutting up the existing fire holes, and using the chimneys as upcast shafts in the manner above described. This may be done in the winter when the problem is easiest and the demand for artificial climate the most urgent, but I question the possibility of summer ventilation and tempering of climate in anything short of a specially built house or a materially altered existing dwelling. There are doubtless some exceptions to this, where the house happens to be specially suitable and easily adapted, but in ordinary houses we must be content with the ordinary devices of summer ventilation by doors and windows, plus the upper openings of the rooms into the chimneys expanded to their full capacity, and thus doing even in summer far better ventilating work than the existing fire holes opening in the wrong place. I thus expound my own scheme, not because I believe it to be perfect, but on the contrary as a suggestive project to be practically amended and adapted by others better able than myself to carry out the details. The feature that I think is novel and important is that of consciously and avowedly applying to domestic ventilation the principles that have been so successfully carried out in the far more difficult problem of subterranean ventilation. The dishonesty of the majority of the modern builders of suburban villa residences is favorable to this and other similar radical household reforms, as thousands of these wretched tenements must sooner or later be pulled down, or will all come down together without any pulling the next time we experience one of those earthquake tremors which visit England about once in a century. Science in Short Chapters by W. Mattia Williams Chapter 48 Home Gardens for Smoky Towns Part 1 The poetical philanthropists of the Shepherd and Shepardess School, if any still remain, may find abundant material for their doleful denunciations of modern civilization on journeying among the housetops by any of our overground metropolitan and suburban railways and contemplating therefrom the panorama presented by a rapid succession of London backyards. The sandy Sahara and the saline deserts of Central Asia are bright and breezy, rural, and cheerful compared with these fowl, soot smeared, lumber-strewn areas of desolation. The object of this paper is to propose remedy for these metropolitan mesal spots by converting them into gardens and shall afford both pleasure and profit to all concerned. A very obvious mode of doing this would be to cover them with glass and thus convert them into winter gardens or conservatories. The cost of this at once places it beyond practical reach, but even if the costs were disregarded, as it might be in some instances such covering in would not be permissible on sanitary grounds. For doleful and dreary as they are, the backyards of London perform one very important and necessary function. They act as ventilation shafts between the house backs of the more densely populated neighborhoods. At one time I thought of proposing the establishment of horticulture home missions for promoting the decimation of flower pot shrubs in the metropolis, and of showing how much the atmosphere of London would be improved if every London family had one little sweet briar brush, a lavender plant, or a hearty heliotrope to each of its members, so that a couple of million of such ozone generators should breed their sweetness into the dank and dead atmospheres of the denser central regions of London. A little practical experience of the difficulty of growing a clean cabbage or maintaining alive any sort of shrub in the midst of our soot drizzle satisfied me that the mission would fail, even though the sweet briars were given away by the district visitors. For these simple, hearty plants perish in a mid-London atmosphere unless their leaves are periodically sponged and syrenched to wash away the soot particles that otherwise close their stomata and suffocate the plant. It is this deposit that stunts or destroys all our London vegetation, with the exception of those trees which, like the plains, have a deciduous bark and cuticle. Some simple and inexpensive means of protecting vegetation from London's soot are therefore most desirable. When the Midland Institute commenced its existence in temporary buildings in Cannon Street, Birmingham in 1854, I was compelled to ventilate my classrooms by temporary devices, one of which was to throw open the existing windows and protect the students from the heavy blast of entering air by straining it through a strong gauze-like fabric stretched over the opening. After a short time, the tami became useless for its intended purpose. Its interstices were choked with a deposit of carbon. On examining this, I found that the black deposit was all on the outside, showing that a filtration of the air had occurred. Even when the tami was replaced by perforated sink, putted into the window frames in the place of glass panes, it was found necessary to frequently wash the sink in order to keep the perforations open. The recollection of this experience suggests that if a gauze-like fabric cheaper and stronger than the tami can be attained and a sort of greenhouse made with it in the place of glass, the problem of converting London backyards into gardens might be solved. After some inquiries and failures in the trial of various cheap fabrics, I found one that is already to be had and well adapted to the purpose. It is called wall canvas, or scrim, is retailed at three and a half pence per yard and is one yard wide. If I am rightly informed, it may be bought in wholesale quantities at about two and a quarter pence per square yard. An example, one farthing per square foot. This fabric is made of course unbleached thread yard, very strong and open in structure. The light passes so freely through it that when hung before a window, the loss of light in the room is barely perceptible. When a piece is stretched upon a frame, a printed placard or even a newspaper may be read through it. The yarn being loosely spun, fine fluffy filaments stand out and bar the interstices against the passage of even very minute carbonaceous particles. These filaments may be seen by holding it up to the light. The fabric being one yard wide and of any length required, all that is needed for a roof or sidewalls as a skeleton made of lines or runs of quartering at three feet distance from each other. The cost of such quartering made of pitch pine, the best material for outside work, is under one penny per foot run, of common white deal about three farthings. Thus, the cost of material for a roof, say a lean to from a wall top to the side of a house, which will be the most commonly demanded form of 30 feet by 10 feet, i.e. 300 square feet, would be 110 feet of quartering, 11 lengths at one pence, that's nine shillings, two pence, 300 square feet of canvas at one and a quarter, that's six shillings, three pence and for nails and tacks, say one shilling, totaling 16 shillings, five pence. The size of the quartering proposed is two and a half by one and a quarter inch, which laid edge-wise would bear the weight of a man on a plank while nailing down the canvas. The canvas has a stout cord-like edge or selvage that holds the nails well. I find that what are called French tacks are well suited for nailing it down. They are made of wire, well pointed, have a good sized flat clout heads and are very cheap. They're incomparably superior to the ordinary rubbish sold as 10 tacks or cut tacks. The construction of such a conservatory is so simple that any industrious artist in a clerk with any mechanical ingenuity could with the aid of a boy do it all himself. No special skill is required for any part of the work and no other tools in a rule, a saw, and a hammer. Side posts and stronger in-rails would in some cases be demanded. I have not been able to fairly carry out this project in as much as I reside in Twickenham, beyond the reach of the black showers of London Soot. I have, however, made some investigations relative to the climate, which results from such enclosure. This was done by covering a small skeleton frame with a canvas, putting it upon the ground over some cabbage plants, etc., and placing registering thermometers on the ground inside and in similar position around the frame. Also, by removing the glass cover of a cucumber frame and replacing it by a frame of which the canvas is stretched. I planted 300 cabbages in November last, in rows on the open ground, and placed the canvas-covered frame over 18 of them. At the present date, March 15, only 26 of the 282 outside plants are visible above the ground. All the rest have been cut off by the severe frost. Under the frame, all are flourishing. I find that the difference between the maximum and the minimum temperature varies with the condition of the sky. In cloudy weather, the difference between the inside and the outside rarely exceeds 2 degrees Fahrenheit, and occasionally there is no difference. In clear weather, the difference is considerable. During the day, the outside thermometer registers from 4 or 5 to 7 or 8 degrees above that within the screen during the sunshine. At night, the minimum thermometers show a difference which in one case reaches 14 degrees, i.e. between 23rd and 24th February, when the lowest temperatures I have observed was reached. The outside thermometer then fell to 8 degrees Fahrenheit, the inside to 22. On the night of the 24th and 25th, they registered 15.5 degrees outside, 25.5 degrees inside. On other or ordinary clear frosty nights, with east and north and northeast winds, the difference has ranged between 4 degrees and 6 degrees, usually within a fraction of the average 5. The uniformity of this during the recent bright frosty nights, followed by warm sunny days, has been very remarkable. So much so that I think I may venture to state that 5 degrees may be expected as the general protecting effect of a covering of such canvas from the mischievous action of our spring frosts which are due to nocturnal radiation into free space. Thus, we obtain a climate, the mean of which would be about the same as outside, but subject to far less variation. How will this affect the growth of plants desirable to cultivate in the provost canvas conservatories? In the first place, we must not expect the results obtainable under glass, which by freely transmitting the bright solar rays and absorbing or resisting the passage of the obscure rays from the heated soil produces during sunshine a tropical climate here in our latitudes. We may therefore at once set aside any expectation of rearing exotic plants of any kind, even our native and acclimated plants, which require the maximum heat of English sunshine, are not likely to flourish. On the other hand, all those which demand moderate protection from sudden frosts, especially from spring frosts, and which flourish when we have a long mild spring and summer, are likely to be reared with a special success. This includes nearly all of our table vegetables, our salads, kitchen herbs, and British fruits, all of our British and mini exotic ferns, and I believe most of our out of door plants, both wild and cultivated. As the subject of ornamental flowers is a very large one, and one with the cultivation of which I have very little practical acquaintance, I will pass it over, but must simply indicate that in respect to ferns, the canvas enclosure offers a combination of most desirable conditions. The slight shade, the comparatively uniform temperature, and the moderated exhalation are just those of a luxuriant fern dingle. Respecting the useful or economic products, I can speak with more confidence, that being my special department in our family or home gardening, which has physical discipline, I have always conducted myself with a minimum of professional aid. My experience of a small garden leads me to give first place to salads. A yard square of rich soil, well managed, will yield a handsome and delicious weekly dish of salad nearly all year round. And at the same rate, seven or eight square yards will supply a daily dish, including lettuces and dives, radishes, spring onions, mustard, and various kinds of crests, and fancy salads, all in a state of freshness otherwise unattainable by the Londoner. My only difficulty has arisen from irregularity of supply. From the small area allowed for salads, I have been oversupplied in July, August, and September, and reduced to indoor or frame-grown mustard and crest during the winter. With the equitable insular climate obtainable under the canvas, this difficulty will be greatly diminished. And besides this, most of the salads are improved by partial shade, lettuces and dives more blanched and delicate than when exposed to scorching sun, radishes less fibrous, mustard, crests, etc., milder in flavor and more succulent. The multitude of savory kitchen herbs that are so sadly neglected in English cookery, especially in the food of the town artisan and clerk, all was scarcely an exception, demand an equitable climate and protection from our destructive spring frosts. These occupy very little space, less even than salads, and are wanted in such small quantities at a time, and so frequently that the hard-working housewife commonly neglects them altogether. Rather than fetch them from the green grocers in their exorbitantly small penny-worths, if she could step into their backyard and gather her parsley, sage, thyme, winter savory, mint, marjoram, bay leaf, rosemary, etc., the dinner would become far more savory, and the demand for the alcoholic substitutes for relishing food proportionably diminished. My strongest anticipations, however, lie in the direction of common fruits, apples, pears, cherries, plums of all kinds, peaches, nectarines, gooseberries, currants, raspberries, strawberries, etc. The most luxuriant growth of cherries, currants, gooseberries, and raspberries I have ever seen in any part of the world that I have visited is where they might be least expected, Viz Norway. Not the south of Norway merely, but more particularly in the valleys that slope from the 500 square miles of the perpetual ice desert of the Justadal down to the Sonja Fjord, latitude 61 degrees to 61.5 degrees, considerably to the north of the northern most of the Shetland Islands. The cherry and current trees are marvelous there. In the garden of one of the farm stations, Sande, I counted 70 fine bunches of red currants growing on six inches of one of the overladen downhanging stems of a current bush. Cherries are served for dessert by simply breaking off a small branch of the tree and bringing it to the table. The fruit almost as many as the leaves. This luxuriance I attribute to two causes. First, that in that part of Norway, the winter breaks up suddenly at about the beginning of June and not until then, when night frosts are no longer possible due to blossoms appear. It was on the 24th August that I counted the 70 bunches of ripe currents. The second cause is the absence of sparrows and other destructive small birds that devour our currents for the seed's sake before they ripen and our cherries immediately upon ripening. These are preceded by the bull finches that feed on the tender hearts of the buds of most of our fruit trees. Those who believe the newspaper myths which represent such thick-billed birds eating caterpillars should make observations and experiments for themselves as I have done. In our canvas conservatories, neither sparrows nor caterpillars nor wasps or other fruit stealers will penetrate nor will the spring frost nip the blossoms that open out in April. All the conditions for full bearing are there fulfilled and the ripening season, though not so intense, will be prolonged. We shall have an insular jersey climate in London where the mean temperature is higher than in the country around, and if I'm not quite diluted, we shall be able to grow the choicest jersey pairs, those that best ripen by hanging on the tree until the end of December and fine peaches which are commonly destroyed by putting forth their blossoms so early. All the 101 varieties of plums and damsons, green gauges, etc. that can grow in temperature climates will be similarly protected from the frosts that kill their early blossoms and the birds and the wasps that will not give them time to ripen slowly. I have little doubt that if my project is carried out, any London householder, whether rich or poor, may indulge in delicious desserts of rich fruit all grown on the sites of their own now dirty and desolate backyards. That of prizes be given for the most prolific branches of cherry and plum trees, gooseberry and current bushes, the gardens of the seven dials and of classic st. Giles may carry off some of the gold metals, and that by judicious economy of space and proper pruning of the trees, the canvass conservatories may be made not only to serve as orchard houses, but also to grow the salads, kitchen herbs, and green vegetables for cookery under the fruit trees or close around their stems. End of Chapter 48 Red by Mickey Lee Rich Chapter 49 of Science and Short Chapters Red by Mickey Lee Rich This is a LibriVox recording. All LibriVox recordings are in the public domain. For more information or to volunteer, please visit LibriVox.org Science and Short Chapters by W. Matthew Williams Chapter 49 Home Gardens for Smoky Towns, Part 2 Among the suitable vegetables, I may name a sort of perennial spinach, which yields a wonderful amount of produce on a small area. Four years ago, I took the house in which I now reside and found the garden overgrown with a weed that appeared like beet, the leaves being much larger than ordinary spinach. I tried in vain to eradicate it, then gave some leaves to my fowls. They ate them greedily. After this, I had some boiled and found that the supposed weed is an excellent spinach, which may be sown broadcast in thick patches without any interspaces and cut down again and again all year round, fresh leaves springing up from the roots until autumn when it throws up tall flowering systems and yields an abundant crop of seeds. I have some now self-sown that have survived the whole of the late severe winter while turnip tops, cabbages, and everything else have perished. I have sown the ordinary spinach seed in the usual manner in rows and comparing it with the self-sown dense patches of this intruder find the latter produces square yard against square yard six or eight times as much of available eatable crop. None of my friends who are amateur gardeners know this variety, but a few days since I called on Messrs James Carter and Company the wholesale seeds man of whole born and described it. They gave me a packet of what they call perpetual spinach beet, which is maybe seen by comparison with the seeds of those I have here of my own growing is probably the same. Messrs Carter and Company tell me that the plant is very little known and the seed scares from want of cultivation and demand. I therefore steps so far aside to describe and recommend it as specially suited for obtaining large crops on small areas. I also recommend a mode of growing cabbages that I found very profitable vis to sow the seeds broadcast in richly manure beds or patches and leave the plants crowding together. Cut them down while very young without destroying the center bud let them sprout again and again. They thus yield a succession of crops every leaf of which is eatable this instead of transplanting and growing large plants which however desirable for sale in the market are far less profitable for home use. Celery may be grown in like manner and cut down young and green for boiling. Some collateral advantages may be fairly anticipated in cases where the backyard is fully enclosed by the campus. In the first place the air coming into the house from the back will be more or less filtered from the grimy irritant particles with which our London atmosphere is loaded besides obtaining the oxygen given off by the growing plants and the ozone which recent investigations have shown to be produced where aromatic plants such as kitchen herbs are growing. Lavender which is very hardy and spread spontaneously might be grown for this purpose. Backdoors might be left open for ventilation without danger of intrusion or of slamming by gusts of wind. The air thus admitted would be tempered both in summer and winter. By wetting the canvas which may easily be done by means of a small garden engine or hands range the exceptionally hot summer days that are so severely felt in London might be moderated to a considerable extent. The air under the canvas being cooler than that in front would enter from below while the warmer air would be pushed upward and outwards to the front. Although such conservatories may be erected as already stated by artisans and other tenants of small houses I do not advocate dependence on this but on the contrary regard them as a more properly constituting landlord's fixtures and recommend their erection by owners of small house properties in London and other large towns. A workman who will pay a trifle extra for such a garden is likely to be a better and more permanent tenant than one who is content with the slovenly squalor of ordinary back premises. I base this opinion on some experience of holding small houses in the outskirts of Birmingham Talbot Street, Winston Green. These have small gardens while most of those around have none. They are held by weekly tenure and during 18 years I have not lost a week's rent from voids. The men who would otherwise shift their dwelling when the change workshops prefer to remain and walk some distance rather than lose their little garden crops and when obliged to leave they usually found me another tenant a friend who has paid them a small tenant right premium for what is left in the garden or for the privilege of getting a house with such a garden. A small garden is one of the best rivals to the fascinations of the tap room. The strongest argument in favour of my canvas conservatories and that which I reserve as the last is that they are likely to become the poor man's drawing room where he may spend his summer evenings, smoke his pipe, contemplate his growing plants and show them in rivalry to his friends rather than slink away from an unattractive home to seek the sensual excitements that ruin so many of our industrious fellow countrymen. As above stated I have not been able practically to test the filtering capabilities of the canvas owing to my residence out of town but since the above was written i.e. on last Wednesday evening I visited the houses of parliament whereas I had been told the ventilation arrangements include some devices for filtering the air by cotton, wool or otherwise. I was much interested on finding that the long experience and many trials of Dr. Percy and his assistant engineer Mr. Prim have resulted in the selection of the identical material which I have chosen and with which the above described experiments have been made. A wall of such canvas surrounds a low region of the houses and all the air that has been destined to have the privilege of being breathed by British legislators is passed through this vertical stream for the purpose of separating from it the sooty impurities that constitute the special abomination of our metropolitan atmosphere and that of our great manufacturing towns. The quantity of sooty material thus arrested is shown by the fact that it is found necessary to take the screens down once a week and wash them. The wash water are coming away in a semi inky condition. I anticipate that the conservatory filters will rapidly clog and therefore require washing. This may easily be done by means of a jet from a hand syringe directed from within outwards especially if the slope of the roof is considerable which is to be recommended. The filtering screen of the House of Parliament is made by sewing the canvas edges together to form a large continuous area then edging the borders of this with tape and stretching it bodily on the stout frame. This method may be found preferable to that which I proposed above and cheaper than I have estimated as only very light intermediate cross pieces would thus be required merely to prevent bagging and parliamentary quartering above described being nine feet apart instead of three. This would reduce the cost of timber to about one half of the above estimate. The perpendicular walls of the conservatory for such a required may certainly be made thus and I think the roof also if the slope is considerable or if in demand the material may be made of greater width than the three feet. So far I have only mentioned backyards but besides these there are many very melancholy front areas called gardens attached to good houses in some of the once suburban but now internal regions of London where the houses stand some distance back from the formally rural highway. These spaces might be cheaply enclosed with canvas and cultivated as kitchen gardens orchard houses flower gardens or furnories thus forming elegant refreshing and profitable vestibules between the highway and the house door and also serve as luxurious summer drawing rooms. The only objection I foresee to these bright enclosures will be their tendency to encourage the consumption of tobacco. The discussion which followed the reading of the preceding paper at the Society of Arts. A member asked if Mr. Williams had observed the effect of wind and rain on his material. Mr. W. P. B. Shepard said that he was interested in a large square in London and he had hoped to hear something about the cultivation of flowers in such places. Last year they tried the experiment with several varieties of flower seeds and they came up and bloomed well in the open ground without any protection whatever. In most London squares the difficulty was to find anyone bold enough to try the experiment at all and nothing but experience would prove what flowers would succeed and what would not. They were so successful last year that several fine bouquets were gathered in July and August and sent to some of the gardening magazines who expressed their astonishment that such good results were possible in the circumstances. If flowers would answer there would of course be more encouragement to try vegetables. One of the practical difficulties which occurred to him with regard to his plan was that the screens would be somewhat unsightly and then again they might shrink from alteration in the temperature and getting wet and dry. He would repeat however that for a very small expense in seeds a very good show of hardy annuals and perennials might be obtained in July and August even in London. Mr. C. Cook said a flower garden had recently been opened in Truery Lane on the side of an old churchyard to which children were admitted and he wished a similar arrangement might be made in some of the squares and crowded neighborhoods such as Golden Square and especially in Lincoln's Enns Fields. There were lots of children playing about in the streets and he wished the good example set by the Templars might be followed. Mr. Liggins as an old member of the Royal Horticulture Society felt a great interest in the subject. Among his poorer neighbors in the district of Kensington cottage and window gardening had been encouraged for some years past prizes having been awarded to those who were most successful much to their gratification. This was a novel idea but he felt quite sure that it would enable those who adopted it to obtain the crops which had been described. There were many collateral advantages which it would be stow on the working classes if largely followed by them especially the one mentioned by Mr. Williams that those who devoted their spare time to the cultivation of fruit and flowers would not be so open to the attractions of the public house. When traveling through the United States some years ago he was much struck with the differences in appearance of the houses and districts where the main liquor law was in force and soon learned to distinguish where it was adopted by the clean cheerful look of the workman's dwellings the neatness of the gardens and the presence of the trees and flowers which in other districts were wanting. He was not a teetotaler himself and was not advocating such restrictions but he could not help notice the contrast and he felt sure that in all our large towns great progress in civilization and morals would be affected if such an attraction were offered to the working classes. He believed there was so much intelligence and good sense among them that if they only knew what could be done in this way they would attempt it and when an Englishman attempted anything he generally succeeded. Mr. William Botley said they were much indebted to Mr. Williams for having called attention to this important subject. He quite agreed with the observations of the last speaker for his own experience in building cottages showed him that the addition of a piece of garden ground had an excellent effect on the social moral and religious welfare of the inmates. It kept them from the public house and the children who were brought up to hoe and weed their parents gardens turned out the most industrious laborers on his property. He had known of instances where houses had been built with flat concrete roofs and covered in with glass so as to form a conservatory in which vegetables and salads grow very well and he believed the cost was little if any more than ordinary slating. The chairman Lord Alfred Churchill in moving a vote of thanks to Mr. Williams said that there could be no doubt that if his suggestions were adopted it would lead to great economy and have many other attractions for the working classes. During the last few years they had heard a great deal about floriculture in windows and no doubt it was an excellent proposal but if they could add to this the growth of vegetables it would have economical advantages also. The proposal to erect temporary conservatories on the roofs of some of these small houses was an admirable one. He saw no reason why he should not have a peach tree growing against many a tall chimney. You would only want a metal lined tub filled with a good mold the warms of the chimney would aid in promoting the growth of the tree and it could be protected from the smoke and frost by this canvas. One point he should like to know was whether the fabric would not become rotted by the weather and perhaps it might be protected by tanning or some chemical preparation. The effect of the canvas and maintaining an equitable temperature was a great consideration. The difference stated by Mr. Williams of about five degrees in winter in many cases would be just enough to save the life of a plant. Practical gardeners knew the value of placing a covering over a peach tree in early spring to keep off the frosts and also to protect it from the attacks of birds. It was also a curious fact that even a slip of wood or slate a few inches wide put on top of a wall to which a fruit tree was nailed acted as a protection from frost. He trusted that Mr. Williams idea would find favor among the working class and thought it was a subject the royal horticultural society might well take up and offer prizes for. He hoped in a short time when that society had passed through a crisis which was impending it might emerge in a condition to devote attention to this matter. It already offered prizes for small suburban flower shows but had not yet turned his attention to the larger class aimed at by Mr. Williams. Mr. Botley said he had forgotten to mention that he has a friend a very excellent gardener who always loosened his fruit trees from the wall for about three weeks before the time of blooming. The consequence was they did not get so much heat from the wall and the bloom was two or three weeks later in forming. After the spring frosts the trees were again nailed up close and he never failed in getting an excellent crop when his neighbors often had none. Mr. Truby wished to caution those who read the paper against using what was commonly known as paper hangers canvas because it was made of two materials hemp and jute and if a piece of it were put into water it would soon be nothing but a lot of strings the jute being all dissolved. It did very well for paper hanging but would be quite unsuitable for this purpose. The vote of thanks having been passed Mr. Williams in reply said he had had a piece of the canvas stretched on a frame exposed all the winter and the only result was to make it rather dirty. He stretched it as tightly as he could in putting it on but when it got wet it became still more tight and gave a little again on becoming dry. It bore the weight of the snow which had fallen very well and two or three spade foals had been added to try it. He had a note from Mr. Prim saying that at the houses of parliament the screens last about two sessions being washed once a week and the destruction is due to the ringing but there is really no occasion for this for if you syringe the stuff well from the inside you make it sufficiently clear to allow the air and light to pass through and it would probably last many years. He had tried the experiment of dipping it in a very weak solution of tar but this had the effect of matting together the fine filaments so that it did not act so effectually as a strainer. It acted best when wet because the fine particles of suit adhered to it and moist weather was just the time when the greatest quantity of soot fell. It might be easily tried in london squares to aid in the growth of flowers. He found that the cabbage plants which were so protective throw remarkably well and he had no doubt that if flowers were planted and a screen put over them until they were ready to bloom it would be a great advantage. The action of a little peat on the top of a wall to protect fruit trees is very simple and the explanation was afforded by the experiments of Dr. Wells on dew. The frosts which did the greatest mischief were due to radiation from the ground on clear nights and it would be found that if one thermometer were placed in a garden under an umbrella and another one on the open ground near it the differences of temperature would be considerable. On cloudy nights there was a very little difference. Last night there was only about a difference of two degrees but a few nights before it was six degrees. The period of greatest cold might not probably be more than hour but it would be sufficient to do a great deal of mischief and anything which would check through radiation would have the required effect. In the case of loosening the fruit trees from the wall there was probably a double action. It prevented the tree being forced on by the warmth or the wall in the daytime and also avoided the chilling effect at night. A rough wall being a good radiator and sinking to a low temperature. He did not think there was much danger to be apprehended from wind because the canvas being so open the wind would pass freely through it but he had not seen it subjected to any violent gale. End of Chapter 49. Home Gardens for Smoky Towns, Part Two. Read by Mickey Lee Rich. Chapter 50 of Science in Short Chapters. This is a LibriVox recording. All LibriVox recordings are in the public domain. For more information or to volunteer please visit LibriVox.org. Recorded by Katie Abattusley. Science in Short Chapters by W Williams. Chapter 50. Solids, Liquors and Gasses, Part One. The growth of accurate knowledge is continually narrowing and often obliterating the broad lines of distinction that have been drawn between different classes of things. I well remember when our naturalists regarded their species of plants and animals as fundamental and inviolable institutions separated by well-defined boundaries that could not be crossed. Darwin has upset all this and now we cannot even draw a clear, sharp line between the animal and vegetable kingdoms. The chemist is even crossing the boundary between these and the mineral kingdom by refuting the once-positive dictum that organic substances i.e. the compounds ordinarily formed in the course of vegetable and animal growth cannot be produced directly from dead matter by any chemical device. Many of such organic compounds are now made in the laboratory for mineral materials. We all know broadly what are the differences between solids, liquids and gases and until lately they have been very positively described as the three distinct states or modes of existence of matter. Mr Crook suggests a fourth. I will not discuss this at present but merely consider the three old established claimants to distinctive existence. A solid is usually defined as a body made up of particles which hold together rigidly or immovably in contra-distinction to a fluid of which the particles move freely over each other. Fluids in the general term including both gases and liquids both being alike as regards to mobility of their particles at present let us confine our attention to liquids and solids. The theoretical or perfect fluid which is imagined by the mathematician as the basis of certain abstract reasoning has no real existence he assumes and the assumption is legitimate and desirable providing its imaginary character is always remembered that the supposed particles move upon each other with perfect freedom without any friction or other impediment but as a matter of fact all liquids exert some amount of resistance to their own flowing they are more or less viscous. Have more or less of that sluggishness in their obedience to the law of finding their own level which we see so plainly displayed by treacle or castor oil this viscosity added to the friction of the liquid against the solid on which it rests or in which it is enclosed may become even in the case of water a formidable obstacle to its flow thus if we make a hole in the side of a tank at a depth of 16 feet below the surface the water will spout from that hole at a rate of 32 feet per second but if we connect with this hole a long horizontal pipe of the same internal diameter as the hole and then observe the flow from the outlet of the pipe we shall find its velocity visibly diminished and we shall be greatly deceived if we make arrangements for carrying swift flowing water thus to any great distances three or four years ago an attempt was made to supersede the water carts of London by laying down on each side of the road a horizontal pipe perforated with a row of holes opening towards the horseway the water was to be turned on and from these holes it was to jet out to the middle of the road from each side and thus water at all i watched the experiment made near the bank of England instead of spouting across the road from all these holes as it would have done from any one of them it merely dribbled the reason being that in order to supply them all the water must run through the hole of the long pipe with considerable velocity and the viscosity and friction to overcome it in doing this nearly exhausted the whole force of waterhead pressure many other similar blunders have been made by those who have sought to convey water power to any distance by means of a pipe of such diameter as should demand a rapid flow through a long pipe the resistance which water offers to the stroke of the swimmer or the pull of the rower is partly due to its viscosity and partly to the uplifting or displacement of some of the water if it were perfectly fluid our movements within it and those of fishes etc would be curiously different the whole face of the globe would be strangely altered in many respects i will not now follow up this idea but leave it as a suggestion for the reader to work out for himself by considering what would remain undone upon the earth if water flowed perfectly without any internal resistance or friction upon the earth's surface the degrees of approach to perfect fluidity vary greatly with different liquids is there any such a thing as an absolute solid or a body that has no degree of fluidity the particles or parts of which will admit of no change of their relative positions no movement upon each other without fracture of the mass this was construed perfect rigidity or the opposite to fluidity take a piece of copper or soft iron wire about one eighth of an inch in diameter or thereabouts and bend it backwards and forwards a few times as rapidly as possible but without breaking it then without loss of time feel the portion that's been bent it is hot painfully so if the experiment is smartly made how may this be explained it is evident that in the act of bending there must have been a displacement of the relative positions of the particles of the metal and the force demanded from the bending indicated their resistance to this movement upon each other or in other words that there was friction between them or something equivalent to such internal friction and thus the mechanical force exerted in the bending was converted into heat force here then with fluidity according to the above definition not perfect fluidity but fluidity attended with resistance to flow or what we have agreed to call viscosity but water also offers such resistance to flow or viscosity therefore the difference between iron or copper wire and liquid water as regards their fluidity is only a difference of degree and not of kind the demarcation between solids and liquids is not a broad clearly divine but a band of blending shade the depth of tint representing varying degrees of viscosity multitudes of examples may be cited illustrating the viscosity of bodies that we usually regard as types of solidity such for example as the rocks form in the earth's crust in the black country of south staffordshire which is undermined by a great 10-yard coal seam cottages chimneys shafts and other buildings may be seen leaning over most grotesquely houses split down the middle by the subsidence or inclination of one side great hollows in the field or across roads that were once flat and a variety of other distortions due to the gradual sinking of the rock strata that has been undermined by the colliery workings in some cases the rocks are split but usually the subsidence is a bending or flowing down of the rocks to fill up the vacuity as water fills a hollow or find its own level i have seen many cases of the downward curvature of a roof of a culpit and have been told that in some cases the surrounding pressure causes the floor to curve upward but have not seen this earthquakes afford another example the so-called solid crust of the earth is upheaved and cast into positive billows that wave away on all sides from the center of disturbance the earth below of the great lisbon earthquake of 1755 traveled to this country and when they reached lock lomond were still of sufficient magnitude to raise and lower its banks through a perpendicular range of two feet four inches it is quite possible or i may say probable that there are tides of the earth as well as of the waters and the subject has occupied much attention and raised some discussion among mathematicians if the earth has a fluid center and only a comparatively thin crust as some supposed there must be such tides produced by the gravitation of the moon and sun ice presents some interesting results of this viscosity at a certain height varying with latitude aspect etc we reach the snow line of mountain slopes above which the snow of winter remains unmelted during summer and in most cases goes on accumulating it soon loses its flocculent flaky character and becomes coherent clear blue ice by the pressure of its own weight a rather complex theory has been propounded to explain this change the theory of regilation i.e. refreezing a theory which assumes that the pressure first thaws a film of ice at the surface of contact and that presently this refreezes and thus affects a healing or general solidification faraday found that two pieces of ice with moist and surfaces united if pressed together when at just above the temperature of freezing but not if much colder tindle has further illustrated this by taking fragments of ice and squeezing them in a mold whereby they become a clear transparent ball or cake schoolboys did the like long before when snowballing with snow at about the thawing point such snow as we all remember became converted into stony lumps when firmly pressed together we also remember that in much colder weather no such cohesion occurred but our snowballs remain powdery in spite of all our squeezing i am sceptic as regards this theory of regilation i believe that the true explanation is much simpler that the crystals of snow or fragments of ice in these experiments are simply welded as the smith unites two pieces of iron by merely pressing them together when they are of near their melting point other metals and other fusible substances may be similarly welded providing they soften or become sufficiently viscous before fusing platinum is a good example of this it is infusible in ordinary furnaces but becomes pasty before melting and therefore one method adopted in the manufacture of platinum ingots or bars from the ore is to precipitate a sort of platinum snow spongy platinum from its solution in acid and then compress this metallic snow in red hot steel molds by means of pistons driven with great force the flocculent metal thus becomes a solid coherent mass just as the flocculent ice becomes a coherent ice in tindall's experiment or in making hard snowballs wax pitch resin and all other solid that fuses gradually cohere are weldable or in very plain language stick together when near their fusing point i have made the following experiment to prove that when this so-called regilation of snow or ice fragments occur the ice is viscous or plastic like wax or pitch a strong iron squirt with a cylindrical ball of half an inch in diameter is fitted with an iron piston this piston is driven forth by a screw working in a collar at one end of the squirt into the other end is screwed a brass nozzle with an aperture about one twentieth of an inch diameter tapering or opening inwards gradually to the half inch ball into this ball i play snow or fragments of ice then holding the body of the squirt firmly in a vice i work the lever of the screw and thus drive forward the piston and crush down the snow or ice fragments which presently become coherent and form a half inch solid cylinder of clear ice applying still more pressure this cylinder is forced like a liquid through the small orifice of the nozzle of the squirt and it jets or spouts out as a thin stick of ice like vermicelli or the leads of ever-pointed pencils from the molding of which the squirt was originally constructed i find that ice at 32 degrees can thus be squirted more easily than beeswax of the same temperature and such being the case i see no reason for imagining any complex operation of regilation in the case of ice but merely regard the addition of two pieces of ice when pressed together as similar to the sticking together of two pieces of cobbler's wax or softening ceiling wax or beeswax or the welding of iron or glass when heated to their welding temperatures i.e to a certain degree of incipient fluidity or viscosity if a lead and bullet be cut in half and the two fresh cut faces pressed forcibly together they could hear at ordinary atmospheric temperatures but we have no occasion for a regilation theory here the viscosity of the lead accounts for all at Woolwich Arsenal there is a monster squirt similar to my little one this is charged with lead and by means of hydraulic pressure the lead is squirted out of the nozzle as a cylindrical jet of any required diameter this jet or stick of lead is the material of which the elongated cylindrical rifle bullets are now made but returning to the point at which we started at the subject of ice viz is alpine accumulation above the snow line if the snowfall there exceeds the amount that is thawed and evaporated it must either go on growing upward until it reaches the highest atmospheric region from which it falls or is formed or it must descend somehow if snow can be squirted through a syringe by mere hand pressure we are justified in expecting that it would be forced down a hill slope or through a gully or across a plane by the pressure of its own weight when the accumulation is great such is the case and thus our glaciers formed they are strictly speaking rivers or torrents of ice they flow as liquid water does and down the same channels as would carry the liquid surface drainage of the hills we're rain to take the place of snow like rivers they flow with varying speed according to the slope like rivers their current is more rapid in the middle than at the sides like rivers they exert the greatest tearing force when squeezed narrow through gullies and like rivers they spread out into lakes where they come upon an open basin like valley with narrow outlets the just double rays of norway is a great ice lake of this character covering a surface about 500 square miles and pouring down its ice torrents on every side wherever there is a notch or valley descending from the table and it covers the rate of flow of such downpouring glaciers varies from two or three inches to as many feet per day and they present magnificent examples of the actual fluidity or viscosity of an apparently solid mass this viscosity has been disputed and attempts have been made to otherwise explain the motion of glaciers but while it is possible that it may be assisted by varying expansion and contraction the down flow due to viscosity is now recognized as unquestionably the main factor of glacier motion cascades of ice may be sometimes seen in the course of my first visit to norway i wandered alone over a very desolate mountain region towards the head of the justadel and unexpectedly came upon a gloomy lake the stigevand which lies at the foot of a precipice boundary of the great ice field above named here the ice having no sloping valley trough by which to descend poured over the edge of the precipice as a great overhanging sheet or cornice which bent down as it was pushed forward and presented on the convex side of the sheet some fine blue crack or crevices as they are called these gradually widened and deepened until the overhanging mass broke off and fell into the lake on the surface of which i saw the result in the form of several floating icebergs that had previously fallen something like this on a small scale may be seen at home on the edge of a house roof on which there has been an accumulation of snow but in this case it is rather sliding than flowing that has made the cornice but its down bending is a result of viscosity these and the multitude of all the facts that might be stated many of which will occur to the reader prove clearly enough that the solid and liquid states of matter are not distinctly and broadly separable but are connected by an intermediate condition of viscosity we now come to the question whether is any similar continuity between liquids and gases ordinarily experience decidedly suggest a negative answer we can point to nothing within easy reach that has the properties of a liquid and gaseous half and half that stands between gases and liquids as pitch and trickle stands between solids and liquids some perhaps may suggest that cloud matter london fog for example is in such an intermediate state this however is not the case white country fog ordinary clouds or the so-called steam that is seen assuming cloud forms as it issues from the spout of a tea kettle or the funnel of a locomotive consists of minute particles of water suspended in air as solid particles of dust are also suspended it has been called a vascular vapor on the supposition that it has the form of minute vesicles like soap bubbles on a very small scale but this hypothesis remains unproven london fog consists of similar particles varnished with a delicate film of coal tar and interspinkled with particles of soot in order to clearly comprehend the above stated question we must define the difference between liquids and gases in the first place they are both fluids as already agreed what then is the central difference between liquid fluidity and gaseous fluidity the expert in molecular mathematics discoursing to his kinematical brethren would produce a tremendous reply to this question he would describe the oscillations gyrations collisions mean freeing paths and mutual obstructions of atoms and molecules and by the aid of a maddening array of symbols arrive at the conclusion that gases unless restrained expand of their own accord while liquids retain definite limits or dimensions the matter-of-fact experimentalist demonstrates the same by methods that are easily understood by anyone i shall therefore both my own sakes and my readers describe some of the latter in the first place we all see plainly that liquids have a surface i.e a well defined boundary and also that gases and less enclosed have not but as this may be due to the invisibility of gas we must question it further the air we breathe may be taken as a type of gases as water may have liquids it has weight as we may prove by weighing a bottle full of air then pumping out the content weighing the empty bottle and noting the difference having weight it presses towards the earth and is squeezed by all that rests above it thus the air around us is constrained air it is very compressible and is accordingly compressed by the weight of all the air above it this being understood let us take a bottle full of water and another full of air and carry them both to the summit of Mont Blanc or to a similar height in a balloon and we shall then have left nearly half of the atmosphere below and thus both liquid and gas will be under little more than half of the ordinary pressure what will happen if we uncork them both the liquid will still display its definite surface and remain in the bottle but not so the gas it will overflow upwards downwards or sideways no matter how the bottle is held and if we tied an empty bladder over the neck before uncorking we should find this overflow or expansion of the gas exactly proportionate to the removal of pressure provided the temperature remained unaltered thus at half the pressure under which a pint bottle was caught the air would measure exactly one quart at one eighth of the pressure one gallon and so on we cannot get high enough for the latter expansion but can easily imitate the effect of a further evaluation by means of an air pump thus we may put one cubic inch of air into a bladder of 100 cubic inches capacity then place this under the receiver of an air pump and reduce the pressure outside the bladder to one hundredths of its original amount with such atmospheric surrounding the one cubic inch of air will plump out the flaccid bladder and completely fill it the pumpability of the air from the receiver shows that it goes on overflowing from it into the piston of the pump as fast as its own elastic pressure on itself is diminished end of chapter 50 recorded by katia battersley chapter 51 of science in short chapters this is a libra vox recording or libra vox recordings are in the public domain for more information or to volunteer please visit libravox.org recording by katia battersley science in short chapters by w matthew williams chapter 51 solids liquids and gases part two numberless other experiments may be made all proving that all gases are composed of matter which is not merely incohesive but is energetically self repulsive so much so that it can only be retained within any bounds whatever by means of some external pressure or constraint for ought we know experimentally the gaseous contents of one of mr. glaciers balloons would outstretch itself sufficiently to occupy the whole sphere of space that's spanned by the earth's orbit providing that space were perfectly vacuous and the balloon were burst in the midst of it the temperature of the expanding gas being maintained here then in this self repulsiveness instead of self-cohesion this absence of self imposed boundary or dimension we have a broad and well marked distinction between gases and liquids so broad that there seems no bridge that could possibly cross it this was believed to be the case until recently such a bridge has however been built and rendered visible by the experimental researchers of dr. andrews but further explanation is required to render this generally intelligible until quite lately it was customary to divide gases into two classes permanent gases and condensable gases or vapours gaseous water or steam was usually described as typical of the latter oxygen hydrogen nitrogen of the former earlier than this many other gases were included in the permanent list but faraday made a serious inroad upon this classification when he liquidified chlorine by cooling and compressing it long after this the gaseous elements of water and the chief constituents of air oxygen hydrogen nitrogen resisted all effort to condense them but now they have succumbed to great pressure and extreme cooling we've thus arrived at a very broad generalization viz that all gases are physically similar to steam i mean of course dry steam i.e true invisible steam and not the cloudy matter to which the name of steam is popularly given that they are all formed by raising liquids above their boiling point just a steam is formed when we boil water and maintain the steam above the boiling point of water but some liquids boil at temperatures far below that at which others freeze liquid chlorine boils at a temperature below that of freezing water and liquid carbonic acid below even that of freezing mercury and liquid hydrogen far lower still these are cases of boiling nevertheless though it seems a paradox according to the ideas we commonly attach to the word but such ideas are based on our common experience of the properties of our commonest liquids viz water when water boils under the conditions of our ordinary experience the passage from liquid to the gaseous state is a sudden leap with no intermediate state of existence that we are able to perceive and the conditions upon which water is converted into steam the liquid into the gas while both at the bottom of our atmospheric ocean are such as to render an intermediate condition rationally as well as practically impossible we find that the expansive energy by which the steam is enabled to resist atmospheric pressure is conferred upon it by its taking into itself and utilizing from its expansive efforts a large amount of calorific energy when any given quantity of water is converted into steam under ordinary circumstances its bulk suddenly becomes above 1700 times greater a cubic inch of water forms about a cubic foot of steam and nearly a thousand degrees of heat 966.6 disappears as temperature all the way stated we must give to the cubic inch of water at 212 degrees as much heat as would raise it to a temperature of 212 plus 966.6 or 1178.6 if it remained liquid this is about the temperature of the glowing coals of a common fire but the steam that has thus taken enough energy to make the water red hot is still at 212 degrees no hotter than the water was while boiling this heat which thus ceases to exhibit itself as temperature is otherwise occupied its energy is partly devoted to the work of increasing the bulk of the water to the above named extent and partly in conferring on the steam is gaseous specialty that is in overcoming liquid cohesion and substituting for its its opposite property of internal repulsive energy which is characteristic of gases my reasons for thus defining and separating these two functions of the so-called latent heat will be seen when we come to the philosophy of the interest in researchers of Dr Andrews as already explained all gases are now proved to be analogous to steam they are matter expanded and rendered self repulsive by heat all elementary matter may exist in either of the three forms solid liquid or gas according to the amount of heat and pressure to which it is subjected I limit this wide generalization to elementary substances for the following reasons many compounds are made up of elements so feebly held together that they become dissociated when heated to a temperature below their boiling point or their condition may otherwise defined by stating that their bonds of chemical energy which hold their elements together are weaker than the cohesion which binds and holds them in the condition of solid or liquid and are more easily broken by the expansive energy of heat to illustrate this let us take two common and well-known oils olive oil and turpentine the first belongs to the class of fixed oils and the second to volatile oils if we apply heat to liquid turpentine it boils passes into the state of gaseous turpentine which is easily condensable by calling it if the liquid result of this condensation is examined we find it to be turpentine as before not so with the olive oil just as this reaches its boiling point the heat which would otherwise convert it to olive oil vapor begins to dissociate its constituents and if the temperature be raised a little higher we obtain some gases but these are the products of the decomposition not gaseous olive oil this is called destructive distillation in olive oil the boiling point and dissociation point are near to each other in the case of glycerine these points are so nearly approximate that although we cannot distill it unbroken under ordinary atmospheric pressure we may do so if some of this pressure is removed under such diminished pressure the boiling point is brought down below the dissociation point and condensable glycerine gas comes over without decomposition sugar affords a very interesting example of dissociation commencing far below the boiling point and going on gradually and visibly with increasing rapidity as the temperature is raised put some white sugar into a spoon and heat the spoon gradually over a smokeless gas flame or spirit lamp at first the sugar melts then becomes yellow barley sugar this color deepens to orange then red then chestnut brown then dark brown then nearly black caramel then quite black and finally becomes a mere cinder sugar is composed of carbon and water the heat dissociates this carbon separates the water which passes off as vapor and leaves the carbon behind the gradual deepening of the color indicates the gradual carbonization which is completed when only the dry insoluble cinder remains an appearance of boiling is seen but this is the boiling of the dissociated water not of the sugar the dissociation temperature of water is far above its boiling point it is 5,072 degrees Fahrenheit under conditions corresponding to those which makes it boiling point 212 degrees if we examine the variations of the boiling point of water as the atmospheric pressure on its surface varies some curious results follow to do this the reader must enjoy some figures they are extremely simple and perfectly intelligible but demand just a little attention following of three columns the first represents atmospheres of pressure are you taking our atmospheric pressure when it supports 30 inches of mercury in the barometer tube as a unit that pressure is doubled trebled etc up to 20 times in the first column the second column states the temperature which water boils when under the different pressures thus indicated and the third column which is the subject of the special study just now shows how much we must rise the temperature of the water in order to make it boil as we go on adding atmospheres of pressure or in other words the increase of temperature due to each increase of one atmosphere of pressure the figures are founded on the experiments of regnaught pressures in atmospheres temperatures in Fahrenheit and rise of temperature for each additional atmosphere one atmosphere temperature 212 two atmospheres temperature 249.5 rise of temperature 37.5 three atmospheres temperature 273.3 rise of temperature 23.8 four atmospheres temperature 291.2 rise of temperature 17.9 five atmospheres temperature 306 rise of temperature 14.8 six atmospheres temperature 318.2 rise of temperature 12.2 seven atmospheres temperature 329.6 rise of temperature 11.4 eight atmospheres temperature 339.5 rise of temperature 9.9 nine atmospheres temperature 348.4 rise of temperature 8.9 10 atmospheres temperature 356.6 rise of temperature 8.2 11 atmospheres temperature 364.2 rise of temperature 7.6 12 atmospheres temperature 371.1 rise of temperature 6.9 13 atmospheres temperature 377.8 rise of temperature 6.7 14 atmospheres temperature 384.2 rise of temperature 6.2 15 atmospheres temperature 390 rise of temperature 6 16 atmospheres temperature 395.4 rise of temperature 5.4 17 atmospheres temperature 400.8 18 atmospheres, temperature 405.9, rising temperature 5.1, 19 atmospheres, temperature 410.8, rising temperature 4.9, 20 atmospheres, temperature 515.4, rising temperature 4.6. It may be seen from the above that with the exception of one irregularity, there is a continual diminution of the additional temperature, which is required to overcome an additional atmosphere of pressure. And if this goes on as per the pressure and temperature advance, we may ultimately reach a curious condition, a temperature at which additional pressure will demand no additional temperature to maintain the gaseous state, or in other words, a temperature may be reached at which no amount of pressure can dense steam into water, or at which the gaseous and liquid states merge or become indifferent. But we must not push this mere numerical reasoning too far, seeing that it is quite possible to be continually approaching a given point without ever reaching it. As when we go on continually halving the remaining distance, the figures in the above do not appear to follow according to such a law, nor, indeed, any other regularity. This probably arises from experimental error, as there are discrepancies in the results of different investigators. They all agree, however, in the broad fact of the gradation above stated, Du Long and Aragot, who directed the experiments of the French Government Commission for investigating this subject, state the pressure at 20 atmospheres to be 418.4, at 21 422.9, at 22 427.3, at 23 431.4, and at 24 atmospheres, the highest experimental limit 435.5, thus reducing the rise of temperature between the 23rd and 24th atmospheres to 4.1. If we could go on heating water in a transparent vessel until this difference became a vanishing quantity, we should probably recognise a visible physical change coincident with this cessation of condensability by pressure. But this is not possible, as glass would become red hot and softened and thus incapable of bearing the great pressure demanded. Besides this, glass is soluble in water at these high temperatures. If, however, we can find some liquid with a lower boiling point, we may go on piling atmosphere upon atmosphere of elastic expansive pressure as the temperature is raised without reaching an unmanageable degree of heat. Liquid carbonic acid, which under a single atmosphere pressure boils at 112 below the zero of our thermometer, may thus be raised to a temperature having the same relation to its boiling point that a red heat has to that of water, and may be still confined within the glass vessel, provided the walls of the vessel are sufficiently thick to bear the strain of the elastic outstriving pressure. In spite of its brittleness, glass is capable of bearing the normal strain, steadily applied, as may be proved by trying to break even a mere thread of glass by direct pull. Dr Andrews thus treated carbonic acid, and the experiment, as I have witnessed its repetition, is very curious. A liquid occupies the lower part of a very strong glass tube, which appears empty above, but this apparent void is occupied by invisible carbonic acid gas, evolved by the previous boiling of the liquid carbonic acid below. We start at a low temperature say 40 degrees Fahrenheit, then the temperature is raised, the liquid boils until it has given sufficient gas or vapour to exert the full expansive pressure or tension due to that temperature. This pressure stops the boiling and again the surface of the liquid is becalmed. This is repeated at a higher temperature, and thus continued until we approach nearly to 88 degrees Fahrenheit, when the surface of the liquid loses some of its sharp outline. Then 88 degrees is reached, and the boundary between liquid and gas vanishes. Liquid and gas have blended into one mysterious intermediate fluid, and in definite fluctuating something is there filling the whole of the tube. An etherealised vapour or visible gas. Hold a red hot poker between your eyes and the light, you will see an upflowing wavy movement of what appears like liquid air. The appearance of this hybrid fluid in the tube resembles this, but is sensibly denser and evidently stands between the liquid and gaseous states of matter, as pitch or treacle stand between solid and liquid. The temperature at which this occurs has been named by Dr Andrews the critical temperature. Here the gaseous and liquid states are continuous, and it is probable that all substances capable of existing in both states have their own particular critical temperatures. Having thus stated the facts in popular outline, I shall conclude the subject by indulging in some speculation of my own on the philosophy of these general facts of natural laws and on some of their possible consequences. As already stated the conversion of water into steam under ordinary atmospheric pressure demands 966.6 degrees of heat over and above that which does the work of raising the water to 212 degrees. Or, otherwise stated, as much heat is at work in a given weight of steam at 212 degrees it would raise the same quantity of water to 1178.6 degrees if it remained liquid. James Watt concluded from his experiments that a given weight of steam, whatever may be its density, or in other words under whatever pressure it may exist, contains the same quantity of heat. According to this, if we reduce the pressure sufficiently to bring down the boiling point to 112 degrees instead of 212 degrees, the latent heat of the steam thus formed would be 1066.6 instead of 966.6. Or, if, on the other hand, we placed it under sufficient pressure to raise the boiling point to 312, the latent heat of the steam would be reduced to 866.6 degrees, i.e. only 866.6 degrees more than would be required to convert the water into steam. If the boiling point were 412 degrees as it is between 19 and 20 atmospheres of pressure, only 766.6 degrees more heat would be required and so on. To we reach the pressure which raised the boiling point to 1178.6 degrees, the water would then become steam without further heating, i.e. the critical point would be reached and thus, if what is right, we can easily determine theoretically the critical temperature of water. Mr Perkins, who made some remarkable experiments upon very high pressure steam many years ago, an exhibited esteem gun at the Adelaide Gallery stated that red hot water does not boil, that if the generator be sufficiently strong to standard pressure of 60,000 pounds, load on the safety valve, the water may be made to exert a pressure of 56,000 pounds on the square inch at the cherry red heat without boiling. He made a number of rather dangerous experiments in thus raising water to a red heat, and his assertion that red hot water does not boil is curious when viewed in connection with Dr Andrews experiments. I cannot tell how he arrived at this conclusion, having been unable to obtain the original record of his experiments and only quote the above second hand. It is worthy of remark that the temperature he names is about 1170 degrees, or that which, if what is right, must be the critical temperature of water. Perkins red hot water would not boil, being then in the intermediate condition. So far we have a nice theory, which not only shows how the critical state of water must be reached, but also its precise temperature. But all this is based on the assumption that what made no mistake. Unfortunately for the simplicity of this theory, Regnault states that his experiments contradict those of what, and prove that the latent heat of steam does not diminish just in the same degree as the boiling point is raised, but that instead of this diminution of the latent heat progresses 30.5% more slowly than the rise of temperature. So that instead of the latent heat of steam between boiling points of 212 degrees and 312 degrees, falling from 966.6 to 866.6 degrees, it would only fall to 895.1 degrees or 69.5 degrees of latent heat for every 100 degrees of temperature. If this is correct, the temperature at which the latent heat of steam is reduced to zero is much higher than 1178.6 and is in fact a continually receding quantity never absolutely reached. But I am not prepared to accept these figures of Regnault as implicitly as it is now done in textbook. It was nearly saying as is now the fashion, seeing that there are not the actual figures obtained by his experiments, but those of his empirical formulae based upon them. His actual experimental figures are very irregular. Thus between steam temperature of 171.6 degrees and 183.2 degrees, a difference of 11.6 degrees, the experimental difference in the latent heat came out as 4.7 degrees. Between steam temperature of 183.2 degrees and 194.8 degrees or 11.6 degrees again, the latent heat difference is tabulated as 8 degrees. Regnault's experiments were not carried to very high temperatures and pressures and indicate that as these advance the deviation what laws diminishes and may finally vanish at about 1500 or 1600 degrees. Where the latent heat would reach zero and there, according to the above, the critical temperature would be reached. Any additional heat applied after this will have but one function to perform, vis the ordinary work of increasing the bulk of the heated body without doing any further in the way of conferring upon it any new self-repulsive properties. Our notions of solids, liquids and gases are derived from our experiences of the state of matter here upon the earth. Could we be removed to another planet? There would be curiously changed. On Mercury water would rank as one of the condensable gases. On Mars as a fusible solid, but what on Jupiter? Recent observations justify us in regarding this as a miniature sun, with an external envelope of cloudy matter, apparently of partially condensed water, but red hot or probably still hotter within. His vaporous atmosphere is evidently of enormous depth and the force of gravitation being on his visible outer surface two and a half times greater than that on our earth's surface. The atmospheric pressure in descending below this visible surface must soon reach that at which the vapor of water would be brought to its critical condition. Therefore we may infer that the oceans of Jupiter are neither of frozen liquid nor gaseous water, but are oceans or atmospheres of critical water. If any fish, birds, swim or fly therein, they must be very critically organised. As the whole mass of Jupiter is three hundred times greater that of the earth, and its compressing energy towards the centre proportional to this, its materials, if similar to those of the earth and no hotter, would be considerably more dense, and the whole planet would have a higher specific gravity. But we know by the movement of its satellites that instead of this, its specific gravity is less than a fourth of that of the earth. This justifies the conclusion that it is intensely hot, for even hydrogen, if cold, would become denser than Jupiter under such pressure. As all elementary substances may exist as solids, liquids or gases, or critically according to the conditions of temperature and pressure, I am justified in hypothetically concluding that Jupiter is neither a solid, a liquid, nor a gaseous planet, but a critical planet, or an orb composed internally of dissociated elements in the critical state and surrounded by a dense atmosphere of their vapours, and those of some of their compounds such as water. The same reasoning applies to Saturn and the other large and rofied planets. The critical temperature of the dissociated elements of the Sun is probably reached at the base of the photosphere, or that region revealed to us by sunspots. When I wrote The Fuel of the Sun, 13 or 14 years ago, I suggested on the above ground the then heretical idea of the red heat of Jupiter, Saturn, Uranus and Neptune, and showed that all such compounds as water must be dissociated at the base of the Sun's atmosphere. But being then unacquainted with the existence of this critical state of matter, I suppose the dissociated elements to exist as gases with a small solid nucleus or kernel in the center. Applying now the researchers of Dr. Andrews to the conditions of solar existence, as I formally apply the dissociation researchers reveal, I conclude that the Sun has no nucleus, either solid, liquid, or gaseous, but is composed of dissociated matter in the critical state, surrounded first by a flaming envelope due to the recombination of the dissociated matter, and outside of this another envelope of vapours due to this combination. End of chapter 51 recorded by Kadia Battersby.