Chapter 24 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. Science in Short Chapters by W. Matthew Williams The Englishman's Fireside During the investment of Paris, the Comte Rendue of the Academy of Sciences were mainly filled with papers on the construction and guidance of balloons, with the results of ingenious researchers on methods of making milk and butter without the aid of cows, on the extraction of nutritious food from old boots, saddles and other organic refuses, and other devices for rendering the general famine more durable. In like manner, our present coal famine is directing an important amount of scientific as well as commercial attention to the subject of economising coal and finding substitutes for it. A few thoughtful men have shocked their fellow sufferers very outrageously by wishing that coal may reach three pounds per ton and remain at that price for a year or two. I confess that, in spite of my own empty coal cellar and small income, I am one of those hard-hearted, cool calculators. Being confident that, even from the narrow point of view of my own outlay and fuel, the additional amount I should thus pay in the meantime would be a good investment, affording by an ample return in the saving due to consequent future cheapness. Regarded from a national point of view, I am convinced that three pounds a ton in London and corresponding prices in other districts, if thus maintained, would be an immense national blessing.   We sacrifice health, we sacrifice comfort, we begrime our towns and all they contain, we expend an amount far exceeding the interest of the national debt and discount our future prospects of national prosperity in order that we may do what. Enjoy the favourite recreation of idiots.  Few sites are more melancholy than the contemplation of a party of English fire worshippers seated in a semi-circle round the family fetish on a keen frosty day. They huddle together, roast their knees and grill their faces in order to escape the chilling blast that is brought in from all the chinks of leaky doors and windows by the very agent they employ at so much cost for the purpose of keeping the cold away. The bigger the fire, the greater the draught, the hotter their faces, the colder their backs, the greater the consumption of coal, the more abundant the crop of chill-blanes, rheumatism, Qatar and other well-deserved miseries. The most ridiculous element of such an exhibition is the complacent self-delusion of the victims. They believe that their idol bestows upon them an amount of comfort unknown to other people, that it affords the most perfect and salubrious ventilation and, above all, that it is a cheerful institution.  The notion that our common fireplaces and chimneys afford an efficient means of ventilation is almost too absurd for serious discussion. Everybody who has thought at all on the subject is aware that in cold weather the exhalations of the skin and lungs, the products of gas burning, etc., are so much heated when given off that they rise to the upper part of the room, especially if any cold outer air is admitted, and should be removed from there before they cool again and descend. Now our fireplace openings are just where they ought not to be for ventilation. They are at the lower part of the room, and thus their action consists in creating a current of cold air, or draft, from doors and windows, which cold current at once descends and then runs along the floor, chilling our toes and provoking chill-blanes. This cold fresh air, having done its worst in the way of making us uncomfortable, passes directly up the chimney without doing us any service for purposes of respiration. Our mouths are usually above the level of the chimney opening, and thus we only breathe the bisciated atmosphere which it fails to remove. Not only does the fire-opening fail to purify the air we breathe, it actually prevents the leakage of the lower part of the windows and doors from assisting in the removal of the upper stratum of bisciated air, for the strong updraft of the chimney causes these openings to be fully occupied by an inflowing current of cold air, which at once descends and then proceeds, as before stated, to the chimney. If the leakage is insufficient to supply the necessary amount of chill-blane making and bronchitis-producing draft, it heads to enter by way of the chimney pot in the form of occasional spasms of downdraft, accompanied by gusts of choking and blackening smoke. It is a fact, not generally known, that smoky chimneys are a special English institutions, one of the peculiar manifestations of our very superior domestic comfortableness. It is true that, in some of our rooms, an Arnot's ventilator opens into the upper part of the chimney, but this was intended by Dr Arnot as an adjunct to his modification of the German stove, and such ventilator can only act efficiently where a stove is used. The pressure required to fairly open it can only be regularly obtained when the chimney is closed below, or its lower opening is limited to that of a stovepipe. The mention of a German stove has upon an English fire worshipper a similar effect to the sight of water upon a mad dog. Again and again, when I have spoken of the necessity of reforming our fireplaces, the first reply elicited has been, What would you have us use German stoves? In every case where I have inquired of the exclamer, what sort of a thing is a German stove? The answer has proved that the exclamation was but a manifestation of blind prejudice based upon total ignorance. These people, who are so much shocked at the notion of introducing German stoves, have no idea of the construction of the stoves which deservedly bear this title. Their notion of a German stove is one of those wretched iron boxes of purely English invention known to ironmongers as shop stoves. These things get red-hot. Their red-hot surface frizzles the dust particles that float in the atmosphere and perfume the apartment accordingly. This, however disagreeable, is not very mischievous. Perhaps the reverse, as many of these dust particles which are revealed by a sunbeam, are composed of organic matter, which, as Dr. Tyndall argues, may be carriers of infection. If we must inhale such things, it is better that we should breathe them cooked than take them raw. The true cause of the headaches and other mischief, which such stoves unquestionably induce, is very little understood in this country. It has been falsely attributed to over-drying of the atmosphere and accordingly evaporating pans and other contrivances have been attached to such stoves, but with little or no advantage. Other explanations are given, but the true one is that iron, when red-hot, is permeable by carbonic oxide. This was proved by the researchers of Professor Graham, who showed that this gas not only can pass through red-hot iron with singular facility, but actually does so whenever there is atmospheric air on one side and carbonic oxide on the other. For the benefit of my non-chemical readers, I may explain that when any of our ordinary fuel is burned, there are two products of carbon combustion. One the result of complete combustion, the other of semi-combustion, carbonic acid and carbonic oxide. The former, though suffocating when breathed alone or in large proportion, is not otherwise poisonous and has no disagreeable odor. It is in fact rather agreeable in small quantities, being the material of champagne bubbles and of those of other effervescing drinks. Carbonic oxide, the product of semi-combustion, is quite different. Breathed only in small quantities, it acts as a direct poison, producing peculiarly oppressive headaches. Besides this, it has a disagreeable odor. It thus resembles many other products of imperfect combustion, such as those which are familiar to everybody who has ever blown out a tallow candle and left the red wick to its own devices. On this account alone, any kind of iron stove capable of becoming red hot should be utterly condemned. If Englishmen did their travelling in North Europe in the winter, their self-conceit respecting the comfort of English houses would be cruelly lacerated and none such would perpetrate the absurdity of applying the name of German Stove to the iron firepots that are sold as stoves by English ironmongers. As the Germans use so great a variety of stoves, it is scarcely correct to apply the title of German to any kind of stove unless we limit ourselves to North Germany. There, and in Sweden, Denmark, Norway and Russia, the construction of stoves becomes a speciality. The Russian stove is perhaps the most instructive to us as it affords the greatest contrast to our barbarous device of a hole in the wall into which fuel is shoveled and allowed to expend nine-tenths of its energies in heating the clouds. While only the residual ten percent does anything towards warming the room. With the thermometer outside below zero, a house in Moscow or St. Petersburg is kept incomparably more warm and comfortable and is better ventilated, though perhaps not so much ventilated than a corresponding class of house in England where the outside temperature is twenty or thirty degrees higher and this with a consumption of about one-fourth of the fuel which is required for the production of British bronchitis. This is done by, first of all, sacrificing the idiotic recreation of far-gazing, and by admitting nowhere into the chimney but that which is used for the combustion of the fuel. Thirdly, by sending as little as possible of the heat up the chimney. Fourthly, by storing the heat obtained from the fuel in a suitable reservoir and then allowing it gradually and steadily to radiate into the apartment on a very large but not overheated surface. The Russian stove by which these conditions are fulfilled is usually an ornamental, often a highly artistic, handsomarticle of furniture made of fire-resisting porcelain glazed and otherwise decorated outside. Finally, it is divided by thick fire-clay walls into several upright chambers or flues, usually six. Some dry firewood is lighted in a suitable fireplace and is supplied with only sufficient air to affect combustion, all of which enters below and passes fairly through the fuel. The products of combustion, being thus undiluted with unnecessary cold air, are very highly heated and in this state pass up compartment or flue number one. They are then deflected and passed down number two, then up number three, then down number four, then up number five, then down number six. At the end of this long journey they have given up most of their heat to the twenty-four heat absorbing surfaces of the fire-clay walls of the six flues. When the interior of the stove is thus sufficiently heated, the fire door and the communication with the chimney are closed and the fire is at once extinguished, having now done its day's work. The interior of the stove has bottled up its calorific force and holds it ready for emission into the apartment. This is affected by the natural properties of the walls of the earthenware reservoir. They are bad conductors and good radiators. The heat slowly passes through to the outside of the stove. They are radiated into the apartment from a large and moderately heated surface, which affords a genial and well-diffused temperature throughout. There is no scorching in one little red-hot hole or corner or box and freezing in the other parts of the room. There are no drafts as the chimney is quite closed as soon as the heat reservoir is supplied. One of these heat reservoirs is placed in the hall where it may form a noble ornament and can easily communicate with an underground flue. It warms every part of the house and enables the Russian to enjoy a luxurious temperate climate indoors in spite of arctic winter outside. In a house thus warmed and free from drafts or blasts of cold air, ventilation becomes the simplest of problems. Nothing more is required than to provide an inlet and outlet in suitable places and of suitable dimensions, when the difference between the specific gravity of the cold air without and warm air within does all the rest. Nothing is easier to arrange than to cause all the entering air to be warmed on its way by the whole stove and to regulate the supply which each apartment shall receive from this general or mainstream by adjusting its own upper outlet. In our English houses with open chimneys all such systematic scientific ventilation is impossible. It is dominating, interfering, useless and comfort destroying currents produced by these wasteful air shafts. I should add that the Russian porcelain reservoirs may be constructed for a heat supply of a few hours or for a whole day and I need say nothing further in refutation of the common British prejudice that can found so admirable and truly scientific a contrivance with the iron firepot above refer to. There is another kind of stove which for the sake of distinction I may call Scandinavian as it is commonly used in Norway, Sweden and Denmark besides some parts of North Germany. This is a tall hollow iron pillar of rectangular section varying from three to six feet in width and rising halfway to the ceiling of the room and sometimes higher. A fire is lighted at the lower part and the products of combustion in their way upwards meet with horizontal iron plates deflect them first to the right then to the left and thus compel them to make a long serpentine journey before they reach the chimney. By this means they give off their heat to the large surface of iron plate and enter the chimney at a comparatively low temperature. The heat is radiated into the apartment from the large metal surface no part of which approaches a red heat. A further economy is commonly affected by placing this iron pillar in the wall separating two rooms so that one of its faces is in each room. Thus two rooms are heated by one fire. One of these may be the kitchen and the same fire that prepares the food that he used to warm the dining room. The fire worshipper is of course deprived of his cheerful occupation of staring at the coals and he also loses his playthings as neither poker, tongs nor coal scuttle are included in the furniture of an apartment thus heated. People differently constituted that an escape from the dust, dirt and clatter of these is a decided advantage. Of course these stoves of our northern neighbours are costly, maybe very costly when highly ornamental. The stove of a Norwegian bonda or peasant proprietor costs nearly half as much as the two-roomed wooden house in which it is erected but the saving it affects renders it a good investment. It would cost one hundred pounds or two hundred pounds to fit up an English mansion with suitable porcelain stoves of the Russian pattern but a saving of twenty pounds a year in fuel would yield a good return as regards mere cost or the gain in comfort and healthfulness would be so great that, once enjoyed and understood such outlay would be willingly made by all who could afford it even if no money saving were affected. Only last week I was discussing this question in a railway carriage where one of my fellow passengers was an intelligent Holsteiner he confirmed the heresy by which I had shocked the others in exalting in the high price of coal and wishing it to continue. He told us that when wood was abundant in his country fuel was used as barbarously as wastefully and as inefficiently as it now is here but that the deforesting of the land and the great cost of fuel was upon them a radical reform the result of which is that they now have their houses better warmed and at a less cost than when fuel was obtainable at one fourth of its present cost. Such will be the case with us also if we can but maintain the present coal famine during one or two more winters especially if we should have the further advantage of some very severe weather in the meantime. Hence the cruel wishes above expressed. The coal famine would scarcely be necessary if we had Russian winters for in such case our houses instead of being as they are merely the most uncomfortable in North Europe would be quite uninhabitable. With our mild winters we require the utmost severity of fuel prices to civilize our warming and ventilating devices. End of The Englishman's Fireside Chapter 25 of Science in Short Chapters This is a LibriVox recording while LibriVox recordings are in the public domain For more information or to volunteer please visit LibriVox.org This is a LibriVox recording by Betty B. Science in Short Chapters by Debia Matia-Williams Chapter 25, Bailey's Beads To the editor of The Times Sir, the curious breaking up of the thin annular rim of the sun which is uncovered just before and just after totality or which surrounds the moon during an annular eclipse has been but occasionally observed as to the accuracy of Bailey's observations has lately arisen. Having attempted an explanation of the beads I have looked with much interest for the reports of the eclipse of 1870. Four, if I am right they ought to have been well seen on this occasion. This has been the case. We are informed that both Lord Lindsay and the Reverend S.J. Perry have observed them and that Lord Lindsay has set aside all doubts respecting their reality by securing a photographic record of their appearance. My explanation is that they are simply sunspots seen in profile spots just caught in the fact of turning the sun's edge. All observers are now agreed as to the soundness of Galileo's original description of the spots that they are huge cavities great rifts of the luminous surface of the sun many thousands of miles in diameter and probably some thousand miles deep. Let us suppose the case of a spot say 2,000 miles deep and 10,000 miles across. Sir W. Herschel has measured spots of 50,000 miles diameter. When such a spot in the course of the sun's rotation reaches that part which forms the visible edge of the sun it must, if rendered visible be seen as a notch.  Only about one 430th of the sun's diameter but the apparent depth would be much less as the edge or rim of the spot next to the observer would cut off more or less of its actual visible depth this amount depending upon the lateral or east and west diameter of the spot in its position at the time of observation. Thus the visible depth of such a notch would rarely exceed one thousandth of the sun's apparent diameter or might be much less. The sun being globular the edge which is visible to us is but our horizon of his fiery ocean which we see a thwart the intervening surface as it gradually bends away from our view. So small an indent upon this edge would under ordinary circumstances of observation be rendered quite invisible by the irradiation of the vast globular surface of the glaring photosphere upon which it would visually encroach. If however this body of glare could be screened off and only a line of the sun's edge less than one thousandth of his diameter remain visible the notch would appear as a distinct break in this curved line of light. If a group of spots or a great irregular spot with several ombre situated upon the sun's edge the appearance of a series of such notches or breaks leaving intermediate detachments of the visible ring of the photosphere would be the necessary result and thus would be presented exactly the appearance described as Bailey's beads. I have been led to anticipate a display of these beads during the late eclipse by the fact that some days preceding it a fine group of spots all to the naked eye through a London fog were traveling towards the eastern edge of the sun and should have reached the limb at about the time of the eclipse. The beads were observed by the Reverend S.J. Perry just where I expected them to appear. I have not yet learned on which side of the sun they were observed and photographed by Lord Lindsay. Bailey's first observation of the beads was made during the annular eclipse of May 15th, 1836. That year, like 1870, was remarkable for a great display of sunspots as in 1870 they were then visible to the naked eye. I well remember my own boyish excitement when a few weeks before the eclipse of 1836 I discovered a spot upon the reddened face of the setting sun. A thing I had read about and supposed that only great astronomers were privileged to see. The focus of the sunspot period is strongly impressed on my memory by the fact that I continued painfully watching the dazzling sun literally watching and weeping up to the Sunday of the eclipse on which day also I saw a large spot through my bit of smoked glass. The previous records of these appearances of fracture of the thin line of light are those of Haley in his memoir on the total eclipse of 1715 and Maclaurins on that of 1737. Both of these correspond to great spot periods. The intervals between 1715, 1737, 1836 and 1870 are all divisible by 11. The observed period of sunspot occurrence is 11 years and a small fraction. I am anxiously awaiting the arrival of Lord Lindsay's long exposure photographs of the corona for if they represent the varying degrees of splendor of the solar appendage the explanations offered in chapter 12 of my essay on the fuel of the sun will be very severely tested by them. Yours respectfully, W. Mattia Williams, Woodside Green, Croydon, January 4th, 1871 End of chapter 25 Chapter 26 of Science in Short Chapters This is a LibriVox recording all LibriVox recordings are in the public domain. For more information auto-volunteer please visit LibriVox.org Recording by Ava Yi in July 2019 Science in Short Chapters by W. Mattia Williams Chapter 26 The Coloring of Green Tea The Coloring of Green Tea The following is a copy of my report to the grocer on a sample of the ingredients actually used by the Chinese for coloring of tea which sample was sent to the grocer office by a reliable correspondent at Shanghai November 1873 I reprinted because the subject has a general interest and is commonly misunderstood. I have examined the blue and the yellowish white powders received from the office and find that the blue is not indigo as your Shanghai correspondent very naturally supposes but is an ordinary commercial sample of Prussian blue. It is not so bright as some of our English samples and by mere casual observation may easily be mistaken for indigo. Prussian blue is a well-known compound of iron, cyanogen and potassium. Commercial samples usually contain a little clayey or other earthy impurities which is the case with this Chinese sample. There are two kinds of Prussian blue the insoluble and the basic or soluble. The Chinese sample is insoluble. This is important seeing that we do not eat our tea leaves but merely drink an infusion of them and thus even the very small quantity which faces the tea leaf remains with the spent leaves and is not swallowed by the tea drinker who therefore need have no fear of being poisoned by this ornamental adulterant. Its unsolubility is obvious from the fact that green tea does not give a blue infusion which would be the case if the Prussian blue were dissolved. There are various facts bearing on this subject and connected with the history of the manufacture of Prussian blue. Masses Bremwell of Newcastle on Tyne who may be called the fathers of this branch of industry established their works about a century ago. It was first sold at two guineas per pound. In 1815 it had fallen to 10 shillings sixpence and then down to one shilling ninepence in 1850. I see by the price current of the oil trade review that the price has recently been somewhat higher. In the early days of the trade a large portion of Masses Bremwell's produce was exported to China. The Chinese then appear to have been the best customers of the British manufacturers of this article. Presently however the Chinese demand entirely seized and it was discovered that a common Chinese sailor who had learned something of the importation of this pigment to his native country came to England in an East India man visited or more probably obtained employment at a Prussian blue manufacturer learned the process and on his return to China started there a manufactory of his own which was so successful that in a short time the whole of the Chinese demand was supplied by native manufacturer and thus ended our export trade.  The yellowish powder is precisely what your Shanghai correspondent supposes. It is steatite or soap stone. The name is very deceptive and coupled with the greasy or unctuous feel of the substance naturally leads to the supposition that it is really as it appears an oleaginous substance. This however is not the case. It is a compound of silica, magnesium and water with which are sometimes associated the little clay and oxide of iron. It has a curiously smooth or slippery surface and hence its name. It nearly resembles the smoothness of which all smokers understand. When soap stone is powdered and rubbed over a moderately rough surface it adheres and forms a shining film just as another unctuous mineral, graphite the black lid of the housemate covers and polishes iron work. On this account soap stone is used in some lubricating compounds for giving the finishing polish to enameled cards and for other similar purposes. With the statement of these properties before us and the interesting description of the process by your Shanghai correspondent the whole riddle of green tea coloring and facing is solved. The Prussian blue and soap stone being mixed together when dry are described. The soap stone adheres to the surface of the particles of blue and imparts to them not only a pale greenish color but also its own unctuous, adhesive and polishing properties. The mixture being well stirred in with the tea leaves covers them with this facing and thus gives both the color and peculiar pearly luster characteristic of some kinds of green tea. I should add that the soap stone like the other ingredient is insoluble and therefore perfectly harmless. Considering the object to be attained it is evident from the above that John Chinaman understands his business and needs no lessons from European chemists. It would puzzle all the fellows of the chemical society though they combined their efforts for the purpose to maximize a more effective, cheap, simple and harmless method of satisfying the foolish demand for unnaturally colored tea leaves. When the tea drinking public are sufficiently intelligent to prefer naturally colored leaves to the ornamental stuff they now select Mr. Chinaman will assuredly be glad enough to discontinue the addition of the Prussian blue which costs him so much more per pound than his tea leaves and will save him the trouble of the painting and varnishing now in demand. In the meantime it is satisfactory to know that although a few silly people may be deceived nobody is poisoned by this practice of coloring green tea. I say a few silly people for there can be only a few and those very silly indeed who judge of their tea by its appearance the quality of the infusion it produces. With these facts before us it is not difficult to trace the origin of the often repeated and contradicted statement that copper is used in coloring green tea. One of the essential ingredients in the manufacture of Prussian blue is sulphate of iron the common commercial name which is green copperus. It is often supposed to contain copper but this is not the case. Your Shanghai correspondent overrates the market value of soapstone when he supposes that Chinese wax may be used as a cheap substitute. In many places as for instance the lizard district of Cornwall great veins of this mineral occur which if needed might be quarried in vast abundance and at very little cost on account of its softness. The romantic scenery of Kynan's Cove, its caverns its natural arches the devil's bellows the devil's post office the devil's cauldrons and other fantastic formations of this part of the coast attributed to his satanic majesty or the druids are the natural results of the waves beating away the veins of soft soapstone and leaving the deformed skeleton rocks of harder serpentine behind. End of section 26 Chapter 27 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 Science in Short Chapters by W. Matthew Williams iron filings in tea I have watched the progress of the tea controversy and the other public performances of the public analysts with considerable interest. It might have been with amusement but for the melancholy degradation of chemical science which they involve. Among the absurdities and exaggerations which for some years past have been so industriously trumpeted forth by the pseudo-chemists who trade upon the adulteration panic and consequent demand for chemical certificates of purity they continually repeated statements concerning the use of iron filings as a fraudulent adulterant of tea take a prominent place. I need scarcely remark that in order to form such an adulterant the quantity added must be sufficiently great to render its addition commercially profitable to an extent commensurate with the trouble involved. The gentlemen who since the passing of the adulteration act have by some kind of inspiration suddenly become full-blown chemists and certified to willful adulteration of tea with iron filings and have obtained convictions on such certificates when, according to their own statement the quantity contained has not exceeded 5% in the cheapest qualities of tea. Now, the price of such tea to the Chinaman tea-grower who is supposed to add these iron filings is about fourpence to sixpence per pound and we are asked to believe that he will fraudulently deteriorate the market value of his commodity for the sake of this additional one-twentieth of weight. Supposing that he could obtain his iron filings at tuppence per pound his total gain would thus be about one-tenth of a penny per pound but can he obtain such iron filings in the quantity required at such a price? A little reflection on a few figures will render it evident that he cannot and that such adulteration is utterly impossible. I find by reference to the grocer of November the 8th that the total deliveries of tea into the port of London during the first ten months of 1872 were 142,429,337 pounds and during the corresponding period of 1873 139,092,409 pounds of this about eight and a half millions of pounds in 1873 and ten millions of pounds in 1872 were green, the rest black. This gives in round numbers about one hundred and sixty millions of pounds of black tea per annum of which above one hundred and forty millions come from China as the Russians are greater tea drinkers than ourselves the Americans and British colonists are at least equally addicted to the beverage and other nations consume some quantity the total exports from China may be safely estimated to reach four hundred or five hundred millions of pounds. Let us take the smaller figure and suppose that only one fourth of this is adulterated to the extent of five percent with iron filings how much would be required just five millions of pounds per annum it must be remembered that coarse filings could not possibly be used they would show themselves at once to the naked eye as rusty lamps and would shake down to the bottom of the chest neither could boreings nor turnings nor plane shavings be used nothing but fine filings would answer the supposed purpose I venture to assert that if the China tea growers were to put the whole world under contribution for their supposed supply of fine iron filings this quantity could not be obtained let anyone who doubts this borrow a blacksmith spice a fine file and a piece of soft iron then take off his coat and try how much labor will be required to produce a single ounce of filings and also bear in mind that fine files are but very little used in the manufacture of iron as the price of a commodity rises when the demand exceeds the supply the Chinaman would have to pay far more for his adulterant than for the leaves to be adulterated as Chinese tea growers are not public analysts we have no right to suppose that they would perpetrate any such foolishness the investigations recently made by Mr. Alfred Byrd of Birmingham show that the iron found in black tea leaves is not in the metallic state but in the condition of oxide and he confirms the conclusions of Zoller quoted by Mr. J. A. Wanklin in the chemical news of October the 10th namely that compounds of iron naturally exist in genuine tea it appears however that the ash of many samples of black tea contains more iron than naturally belongs to the plant and accepting Mr. Byrd's statement that this exists in the leaf as oxide mixed with small silicaeus and mycoceus particles I think we may find a reasonable explanation of its presence without adopting the pure old theory of the adulteration maniac in his endeavour to prove that everybody who buys or sells anything is a swindler has at once assumed the impossible addition of iron filings as a make-weight in the first place we must remember that the commodity in demand is black tea and that ordinary leaves dried in an ordinary manner are not black but brown tea leaves however contain a large quantity of tannin a portion of which is when heated in the leaves rapidly convertible into gallotanic or tannic acid thus a sample of tea rich in iron would when heated in the drying process become by the combination of this tannic acid with the iron it contains much darker than ordinary leaves or than other teas grown upon less veruginous soils and containing less iron this being the case and a commercial demand for black tea having become established the tea grower would naturally seek to improve the colour of his tea especially of those samples naturally pour in iron the ready mode of doing this is offered by stirring in among the leaves while drying a small additional dose of oxide of iron if he can find an oxide in such a form that it will spread over the surface of the leaf as a thin film now it happens that the Chinaman has lying under his feet an abundance of material admirably adapted for this purpose that is red hematite some varieties of which are as soft and unctuous as graphite and will spread over his tea leaves exactly in the manner required the mycachius and silicaeus particles found by Mr Bird are just what should be found in addition to oxide of iron if such hematite were used the film of oxide thus easily applied and subjected to the action of the exuding and decomposing extractive matter of the heated leaves would form the desired black die or facing the knotty question of whether this is or is not an adulteration is one that I leave to lawyers to decide for those debating societies that discuss such interesting questions as whether an umbrella is an article of dress if it is an adulteration and as already admitted is not at all injurious to health then all other operations of dying are also adulterations for the other dyers like the Chinaman curities to their goods the silk wool or cotton in order to alter their natural appearance and to give them the false facing which their customers demand but with this difference if I am right in the above explanation that in darkening tea nothing more is done but to increase the proportion of one of its natural ingredients and to intensify its natural colour while in the dyeing of silk cotton or wool ingredients are added which are quite foreign and unnatural and the natural colour of the substance is altogether falsified the above appeared in the chemical news November the 21st 1873 when the adulteration in question was generally believed to be commonly perpetrated and many unfortunate shopkeepers had been and were still being summoned to appear at petty sessions etc and publicly branded as fraudulent adulterers on the evidence of the newly fledged public analysts who confidently asserted that they found such filings mixed with the tea some discussion followed in subsequent numbers of the chemical news but it only brought out the fact that finally divided iron exists in considerable quantities in Sheffield may be begged as Mr. Alfred H. Allen enable analytical chemist resident in Sheffield said the fact that such finally divided iron is thus without commercial value still further confirms my conclusion that it is not used for the adulteration of tea if it were its collection would be a regular business and truckloads would be transmitted from Sheffield to London the great centre of tea importation no evidence of any commercial transactions in iron filings or iron dust for such purposes came forward in reply to my challenge the practical result of the controversy is that iron filings are no longer to be found in the analytical reports of the adulteration of tea end of iron filings in tea Chapter 28 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 Recording by Anita Sloma-Martinez Science in Short Chapters by W. Machu-Williams Chapter 28 Concert Room Acoustics The acoustics of public buildings are now occupying considerable attention in London The vast audiences which any kind of sensational performance in the huge metropolis is capable of attracting is forcing the subject upon all who cater for public amusement or instruction There was probably no building in London or anywhere else more utterly unfit for musical performances than the Crystal Palace in its original condition But nevertheless the Handel Festival of last week was a great success I attended the first of these immense gatherings and this last but nothing of the kind intermediate and therefore I'm the better able to make comparisons My recollections of the first were so very unsatisfactory that I gladly evaded the grand rehearsal of Friday week and went to the Messiah on Monday with an astronomical treatise in my pocket in order that my time should not be altogether wasted Being seated at the further end of the transept in a gallery above the level of the general ridge and furrow roof of the nave, the plump little Birmingham tenor who rose to sing the first solo appeared under the combined optical conditions of distance and vertical foreshortening like a chubby cheese might of an ocular microscope Taking it for granted that his message of comfort could not possibly reach my ear I determined to anticipate the exhortation by settling down for a comfortable reading of a chapter or two but was surprised to find I could hear every note both of recitative and air It thus became obvious that the alterations that have gradually grown since the time of the trancep was the only one that could be heard across the transep are worthy of study that the advertised success of the Valerium is something more than mere puffery I accordingly used my eyes as well as my ears and made a few notes which may be interesting to musical and architectural as well as to scientific readers Sound like light, heat and space intensity as it is outwardly dispersed is enfeebled in the ratio of the squares of distance thus at 20 feet from the singer the loudness of the sound is one fourth of that at 10 feet at 30 feet one ninth at 40 feet one sixteenth at 50 feet one twenty fifth and so on that is supposing the singer can still air but this condition is never fulfilled in practice accepting perhaps by Simeon's delights when he preached to the multitude from the top of his column if Mr. Vernon Rigby had stood on the top of one of his native South Stratfordshire chimney shafts of the same height above the ground as the upper-press gallery of the crystal palaces above the front of the orchestra and I had stood on the open ground at the same distance away and below him his solo of comfort you my people would have been utterly inaudible what then is the reason of this great difference of effect at equal distances if we can answer this question we shall know something about the acoustics of concert rooms the uninitiated reader will at once begin by saying that sound rises to the left and yet it is a great mistake as commonly understood sound radiates equally in every direction downwards upwards north south east or west and thus some special directive agency is used the directive agency commonly used is a reflecting or reverberating surface thus the voice of the singer travels forward more abundantly than backward because he uses the roof and to some extent the walls and floor of his mouth as a sound reflector the roof of his mouth being made of concave plates of bone with a thin valarium of integument stretched tightly over them supplies a model sound reflector and I strongly recommend every architect who has to build a concert or lecture room or theater to study the roof of his own mouth and imitate it as nearly as he can in the roof of his building the great Italian singing masters of the old school who like the father of Perciani could manufacture a great voice out of average raw material studied physiology of the vocal organs and one of their first instructions to their pupils was that they should sing against the roof of the mouth then throw the head back and open the mouth so that the sound should reverberate as clear of the teeth and lips for the first year or two the pupil had to sing only la-la for several hours per day until the faculty of doing this effectually and habitually was acquired the popular notion that sound rises has probably originated from the fact that in our common experience the sounds are produced near to some kind of floor which reflects the sounds upwards and thus adds the reflected sound to that which is directly transmitted and thereby the general result is materially augmented but if we would economize sound more effectively we must have not only a reflecting floor but also a reflecting roof and reflecting walls on all sides of the concert room these are the conditions that were wanting in the original structure of the crystal palace transept for then the sound of the singer's voice could travel upwards to that lofty arch and sideways in all directions almost as freely as in the open air this defect has been remedied to a very great extent by the valarium stretched across from the springing of the great arch of glass and iron and forming a ceiling to the concert room part of the building besides this a wall of drapery is stretched across each side of the transept and the orchestra has its special walls, roof and back there are other minor arrangements for effecting lateral reverberation that is for returning the sound into the auditorium proper instead of allowing it to wander feebly throughout the building the general result of these arrangements is to render that portion of the building in which the reserved seats are placed are really luxurious and efficient concert room of magnificent proportions but very unfortunately and inevitably these conditions which are so favorable for the happy eight or nine thousand who can afford reserved seats render the position of the other half dozen thousand outsiders more disappointing and fixatious than ever for my own part I would rather spend a holiday afternoon in the mild atmosphere and the quiet soothing gloom of a coal pit then be teased and irritated by a strange listening to the indefinite roar of a grand choir and the occasional dying vibrations of Sims Reeves top A I have in the above advocated reverberation as a remedy for diffusion of sound this may perhaps appear rather startling to some musicians have a well founded dread of echoes and who read the words echo and reverberation as synonymous this requires a little explanation as light is transmitted reflected and absorbed in the same manner of sound and as light is visible or rather renders objects visible I will illustrate my meaning by means of light let us suppose three apartments of equal size in the same shape one having its walls covered with mirrors the second with white paper and the third with black woolen cloth and all lighted with central chandeliers of equal brilliancy the first and second will be much lighter than the third but they will be illuminated very differently in the first there will be a repetition of chandeliers in the mirrored walls each wall definitely reflecting this particular light in the second room there will be reflection also an economy of light but no reflection of definite images the apartment will appear to be filled with a general and well diffused luminosity rendering every object distinctly visible and there will be no deep shadows anywhere in scientific language we shall have in the first room regular reflection scattering reflection in the third room we should have comparative gloom owing to the absorption of the light by the black cloth we may easily suppose the parallels of these in the case of sound if the valarium and sidewalls of the transept and orchestra were made of sheet iron or smooth bare unbroken vibrating wooden boards we should have a certain amount of regular reflection of sound or echo just as we should see the particular lights of the chandelier reflected in the first room so should be here the particular notes of the singer or player echoed by such regularly vibrating walls and ceiling if again the valarium and side drapery of the transept and orchestra had been thick, soft woollen cloths the sound, like the light would have been absorbed or muffled but here it would be weak and insufficient the reader will now ask what then is the right material for such valarium and walls I cannot pretend to say what is the best possible believing that it is yet to be discovered the best yet known and attainable at moderate expense is common canvas or calico washed or painted over with a mixture of size and lime of a material that will fill up the pores of the fabric and give it a moderately smooth facer surface thus prepared it is found to reflect sound as paper, ground glass, etc reflect light by scattering reverberation but without definite echo it will now be understood how the valarium acted in rendering the solo so clearly audible at the great height and distance of the upper press gallery instead of being wasted by diffusion in the great vault above they were stopped and reflected by the valarium but not so reflected as to produce disagreeable repetition notes just audible at particular points as the lights of the mirror reflections of the chandeliers would be flat surfaces reflect radially while concave surfaces with curves reflect sound light, heat, etc in parallel lines the walls and roof of a music hall should scatter their reflections on all sides and therefore should be flat or nearly so accepting at the angles which should be curved or hollowed from the orchestra the sound is chiefly required to be projected forward as from the singer's mouth and therefore an orchestra should have curved walls and roof space will not permit a dissertation here on the particular curve required this has, I believe, been carefully calculated in constructing the crystal palace orchestra viewed from a distance the whole orchestra is curiously like a huge wide-opened mouth that only requires to close a little and open a little more according to the articulations of the choir to represent the comfort of one gigantic throat there is, I think, one fault to the shape of this mouth it extends too far laterally in proportion to its perpendicular dimensions the angles of the mouth are too acute the choir extends too far on each side the singers should be packed more like those of the Birmingham Festival Choir there is an acoustic limit to the magnitude of choirs the choir travels at about 1,100 feet per second and thus, if one of the singers of a choir is 110 feet nearer than another singer to any particular auditor the near singer will be heard one tenth of a second before the more distant though they actually sing exactly together in rapid staccato passages this would produce serious confusion though in such music it would be scarcely observable some observations which I have made convince me that the actual choir of the Handel festivals has reached, if not exceeded the acoustic limits even for Handel's music and decidedly exceeds the limits permissible from Mendelssohn and most other composers I found that when standing on the floor of the building in front of the orchestra it plainly distinguished the wave of difference of time due to the traveling of the sound and in all the passages which required to be taken up smartly and simultaneously by the opposite sides of the choir the effect was very disagreeable the defect however was not observable from the press gallery which is placed as nearly as maybe to the focus of the orchestral curve so that radio lines drawn from the auditor to different parts of the orchestra do not differ so much in length as to affect perceptible differences in the moment at which the different sounds reach the ear my conclusion therefore is that if any amendment is to be made in the numbers of the Handel festival choir it should rather be done by a reduction than an increase that the 4,000 voices should rather be reduced to 3,000 than increased to 5,000 with greater severity of selection as regards quality, power and training of each individual voice and with better packing the 3,000 would be more effective than the 4,000 a rather startling paper in the current number of the quarterly Journal of Science from the Pan of William Crook's FRS who is well known in the scientific world by his discovery of the metal thallium which is the first of the four chapters of the journal of science which is the first of the four chapters of the journal of science which is the first of the four chapters of the journal of science which is the first of the four chapters of the journal of science which is the first of the four chapters of the journal of science which is the first of the four chapters of the journal of science which is the first 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Nobody acquainted with Mr. Crooks can doubt his ability to conduct such an investigation or will hesitate for a moment in concluding that he has done so with philosophical impartiality, though many think it quite possible that he may have been deceived. None, however, can yet say how. For my own part I abstain from any conclusion in the meantime, until I have time and opportunity to witness a repetition of some of these experiments and submitting them to certain tests, which appear to me desirable. Though struggling against a predisposition to prejudge, and to conclude that the phenomena are the result of some very skillful conjuring, I very profoundly respect the moral courage that Mr. Crooks has displayed in thus publicly grappling with a subject which has been soiled by contact with so many dirty fingers. Nothing but a pure love of truth overpowering every selfish consideration could have induced Mr. Crooks to imperil his hard-earned scientific reputation by stepping thus boldly on such very perilous ground. It is only fair at the outset to state that Mr. Crooks is not what is called a spiritualist. This I infer both from what he has published and from conversation I had with him on the subject. He has witnessed some of the physical manifestations, and while admitting that many of these may be produced by the jugglery of imposters, he has concluded that others cannot be thus explained, but nevertheless does not accept the spiritual theory which attributes them to the efforts of departed human souls. He suspects that the living human being may have the power of exerting some degree of force or influence upon body's external to himself, may, for instance, be able to counteract or increase the gravitation of substances by an effort of the will. He calls this power the psychic force, and supposes that some persons are able to manifest it much more powerfully than others and thus explains the performances of those mediums who are not mere imposters. There is nothing in this hypothesis which the sternest, the most skeptical, and least imaginative of physical philosophers may not unhesitatingly investigate, provided some first sight evidence of its possibility is presented to him. We know that the torpedo, the gymnatus, the sylerous electricus, and other fishes can by an effort of the will act upon body's external to themselves. Faraday showed that the electric eel, exhibited some years ago at the Adelaide Gallery, was able by an effort of its will to make a magnetic needle suddenly turn 30 degrees aside from its usual polar position. That is, the same animal could, still by an effort of will, overpower the gravitation of pieces of gold leaf, cause them to be uplifted and outstretched from their pendant position could decompose iodide of potassium and perform many other physical manifestations, simply by a volunteer nervous effort and without calling in the aid of any souls or other departed eels. Before the gymnatus was publicly exhibited, it was deposited at a French hotel in the neighborhood of Lychester Square. A birdly fishmonger's man named Wren brought in the daily supply of fish to the establishment when some of the servants told him they had an eel so large that he would be afraid to pick it up. He laughed at the idea of being afraid of an eel and when taken to the top, boldly plunged in both hands to seize the fish. A hideous roar followed this attempt. Wren had experienced a demonstration of the psychic force of the electric eel and his terror so largely exaggerated the actual violence of the shock that he believed for the remainder of his life that he was permanently injured by it. He had periodical spasms across the chest which could only be removed by taking a half-quarter in a gin and he was continually narrating his adventure to public house audiences and always had a spasm on concluding, which his hearers usually contributed to relieve. The poor fellow's life was actually shortened by the shock of the gymnatus. The experiments which Mr. Crookes relates in support of his psychic force hypothesis are as follows. In the first place, he contrived an apparatus for testing Mr. Holmes' alleged power of modifying the gravitation of bodies. As Mr. Holmes requires to lay his hands or at least his finger ends upon the body to be influenced, Mr. Crookes attached one end of a long board to a suspended spring steel yard of delicate construction. The other end of the board rested on a fulcrum in such a manner that one half of the weight of the board was supported by the fulcrum and the other half by the steel yard. The weight of the board thus suspended was carefully noted and then Mr. Holmes put his finger upon that end of the board immediately resting on the fulcrum in such a manner that he could not by simple pressure affect the dependent end of the board. Dr. Huggins, the imminent astronomer was present and also Sergeant Cox, besides Mr. Crookes. They all watched Mr. Holmes, the board, and the steel yard. They observed first a vibration and fluctuation of the index and finally that the steel yard indicated an increase of weight amounting to about three pounds. Mr. Crookes tried to produce the same effect by mechanical pressure exerted in a similar manner but failed to do so. The details of the experiment are fully described and illustrated by an engraving. Another and still more striking experiment is described. Mr. Crookes purchased a new accordion from Messer's Weedstone and himself constructed a wire cage open at top and bottom and large enough for the accordion to be suspended within it by holding it over the open top while the bottom of the cage rested on the floor. The accordion was then handed to Mr. Holmes, who held it with one hand by the wooden framework of the bottom of the instrument as shown in an illustrative drawing. The keys were thus hanging downward and the bellows distended by the weight of the instrument, thus pendant. It was then held so that it should be entirely surrounded by the wire work of the cage and the results were as before watched keenly by Mr. Crookes, Dr. Huggins, and Sergeant Cox. After a while, the instrument began to wave about. Then the bellows contracted and the lower part, i.e. the keyboard end, rose a little. Presently sounds were produced and finally the instrument played a tune upon itself in obedience as Mr. Crookes opposes to the psychic force which Mr. Holmes exerted upon it. Before the publication of the paper describing these experiments, a proof was sent to both Dr. Huggins and Sergeant Cox and each has written a letter testifying to its accuracy, which letters are printed in the paper in the quarterly journal of science. Here then we have the testimony of an imminent lawyer, accustomed to sifting evidence that of the most distinguished of experimental astronomers, the man whose discoveries in celestial physics have justly excited the admiration of the whole civilized world. And besides these, of another fellow of the Royal Society who has been severely trained in putting nature to the torture by means of the most subtle devices of the modern physical and chemical laboratory. Such testimony must not be treated lightly. It would be simple impertinence for any man dogmatically to assert that these have been deceived merely because he is unconvinced. Though one of the unconvinced myself, I would not dare to regard the investigations of these gentlemen with any other than the profoundest respect. Still, a suggestion occurs to me, which may appear very brutal, but I make it nevertheless. It is this, that the testimony of another witness, of an expert of quite a different school should have been added. I mean such a man as Dobler Houdin or the Wizard of the North. He might possibly have detected something which escaped the scrutiny of the legitimate scientific experimentalist. There is one serious defect in the accordion experiment. The cage is represented in the engraving as placed under a table. Mr. Holm holds the instrument in his hand, which is concealed by the table. And it does not appear that either Mr. Crooks, Dr. Huggins, or Sergeant Cox, placed themselves under the table during the concertina performance, and thus neither of them saw Mr. Holm's hand. Such, at least, appears from the description and the engraving. A story being commonly circulated respecting some of Mr. Holm's experiments in Russia, according to which he failed entirely when a glass table was provided instead of a wooden one. It would be well, if only injustice to Mr. Holm, to get rid of the table altogether. It is very desirable that these experiments should be continued for two distinct reasons. First, as a matter of ordinary investigation for philosophical purposes. And secondly, as a means of demolishing the most degrading superstition of this generation. If Mr. Crooks succeeds in demonstrating the existence of the psychic force and reducing it to law, as it must be reducible if it is a force, then the ground will be cut from under the feet of spiritualism, just as the old superstitions, which attributed thunder and lightning to divine anger were finally demolished by Franklin's kite. If, on the other hand, the arch medium, Mr. Holm, is provided to be a common conjurer, then surely the dupes of the smaller mediumistic fry will have their eyes opened, provided the cerebral disturbance, which spiritualism so often induces, has not gone so far as to render them incurable lunatics. It's very likely that I shall be accused of gross uncharitableness, and thus applying the term lunatics to those who differ from me, and therefore state that I have sad and sufficient reasons for doing so. The first spiritualist I ever knew, and with whom I had many conferences on the subject many years ago, was a lady of most esteemable qualities, great intellectual attainments, and distinguished literary reputation. I watched the beginning and the gradual progress of her spiritual investigations, as she called them, and witnessed the melancholy end, shocking delusions, and intellectual shipwreck, and confirmed incurable insanity, directly and unmistakably produced by the action of these hideous superstitions upon an active, excitable imagination. I well remember the growing symptoms of this case, have seen their characteristic features repeated in others, and have now before me some melancholy cases where the same changes, the same decline of intellect, and growth of ravenous credulity as progressing with most painfully visible distinctness. The necessity for some strong remedy is the more urgent in as much as the diabolical machinery of the spiritual imposter has been so much improved of late. The ladies whose case I first referred to has reached the highest state of spiritualistic development, the Viz, the lunatic asylum, before dark seances had been invented or at any rate before they were introduced into this country. When the conditions of these seances are considered, it's not at all surprising that persons of excitable temperament, especially women, should be morbidly affected by them. We are endowed with certain faculties and placed in a world wherein we must exercise them healthfully upon their legitimate objects. Such exercise, properly limited, promotes the growth and vigor of our faculties. But if we pervert them by directing them to illegitimate objects, we gradually become mad. God has created the light and fitted our eyes to receive it. He has endowed us with a sense of touch by which we may confirm and verify the impressions of sight. All physical phenomena are objects of sense and the senses of sight and touch are the masters of all the other senses. Can anything then be more atrociously perverse, more utterly idiotic, and I may even say impious than these dark seance investigations? It's possible to conceive a more melancholy spectacle of intellectual degradation than that presented by a group of human victims assembled for the purpose of investigating physical manifestations and submitting, as a primary condition, to be blinded and handcuffed, the room in which they sit being made quite dark and both hands of each investigator being firmly held by those of his neighbors. That is to say, the primary conditions of making these physical investigations is that each investigator shall be deprived of his natural faculties for doing so. When we coupled this with the fact that these meetings are got up publicly advertised by adventurers who make their livelihood by the fees paid by their hoodwinked and handcuffed customers, is it at all surprising that those who submit to such conditions should finish their researches in a lunatic asylum? The gloom, the mystery, the unearthly objects of search, the mysterious noises and other phenomena so easily manipulated in the presence of those who can see nothing and feel only the sympathetic twitching of another pair of trembling hands naturally excites very powerfully the poor creatures who pay their half crowns and half guineas with any degree of faith. And this unnatural excitement, if frequently repeated, goes on increasing till the brain becomes incurably diseased. Present space will not permit me to enter upon another branch of the subject, Viz. The moral degradation and perversion of natural, unsophisticated and wholesome theology, which these spiritual delusions are generating. I am no advocate for rectifying moral and intellectual evils by police interference. Or I should certainly recommend the bracing air of Dartmoor for the mediums who publicly proclaim that their familiar spirit, Katie, has lately translated a lady through the space of three miles and through the walls, doors and ceiling of a house in which a dark seance was being held and placed her upon the table in the midst of the circle so rapidly that the word onions, she had just written in her domestic inventory was not yet dried when the lights were brought and she was found there. This lady, which her name is Guppy, is of course another professional medium. And yet there are people in London who gravely believe the story and also the appendix, Viz, that another member of the mediumistic firm finding that Mrs. G was very incompletely dressed and much abashed thereby was translated by the same spirit, Katie, to her house and back again through the door panel to fetch proper garments. If I could justify the apprehension and imprisonment of poor gypsy fortune tellers, I certainly should advocate the close confinement of Mrs. Guppy and her male associates and thus afford the potent spirit, Katie, an opportunity of further manifestation by translating them through the prison walls and back to the lambs conduit street. The above letter appeared in the Birmingham Morning News of July 18, 1871. The following on November 15th. It refers to an article in the quarterly review of October, 1871. The interest excited by Mr. Crook's investigations on psychic force is increasing. The demand for the quarterly review and the quarterly journal of science is so great that Muti and other proprietors of lending libraries have largely increased their customary supplies and are still besieged with further excess of demand. Not only borrowers but purchasers are also supplied with difficulty. I yesterday received a postcard from a bookseller and scribed as follows. Cannot get a quarterly review in the city so shall be unable to send it to you until tomorrow. I have waited three days and am now obliged to go to the reading room to make my quotations. There is good and sufficient reason for this independently of the absence of parliamentary and war news and the dearth of political revolutions. Either a new and most extraordinary natural force has been discovered or some very imminent men specially trained in rigid physical investigation have been the victims of a marvelous, unprecedented and inexplicable physical delusion. I say unprecedented because although we have records of many popular delusions of similar kind and equal magnitude and speculative delusions among the learned, I can cite new instance of skillful experimental experts being utterly and repeatedly deceived by the mechanical action of experimental tests apparatus carefully constructed and used by themselves. As the interest in this subject is rapidly growing, my readers will probably welcome a somewhat longer gossip on this than I usually devote to a single subject. Such an extension is the more demanded as the newspaper and magazine articles which have hitherto appeared have for the most part by following the lead of the quarterly review strangely muddled the whole subject and misstated the position of Mr. Crooks and others. In the first place, all the writers who follow the quarterly omit any mention or allusion to Mr. Crooks preliminary paper published in July, 1870 which has a most important bearing on the whole subject as it expounds the object of all the subsequent researches. Mr. Crooks there states that some weeks ago the fact that I was engaged in investigating spiritualism so-called was announced in a contemporary, the anathema and in consequence of the many communications I have since received, I think it desirable to say a little concerning the investigations which I have commenced. Views or opinions I cannot be said to possess on a subject which I do not profess to understand. I consider the duty of scientific men and who have learned exact modes of working to examine phenomena which attract the attention of the public in order to confirm their genuineness or to explain if possible the delusions of the honest and to expose the tricks of the deceivers. He then proceeds to state the case of science versus spiritualism thus. The spiritualism tells of bodies weighing 50 or 100 pounds being lifted up into the air without the intervention of any known force but the scientific chemist is accustomed to use a balance which will render sensible a weight so small that it would take 10,000 of them to weigh one grain. He is therefore justified in asking that a power professing to be guided by intelligence which will toss a heavy body to the ceiling shall also cause his delicately poised balance to move under test conditions. The spiritualist tells of rooms and houses being shaken even to injury by superhuman power. The man of science merely asks for a pendulum to be sent vibrating when it is in a glass case and supporting on solid masonry. The spiritualist tells of heavy articles of furniture moving from one room to another without human agency but the man of science has made instruments which will divide an inch into a million parts and he's justified in doubting the accuracy of the former observations. If the same force is powerless to move the index of his instrument one poor degree. The spiritualist tells of flowers with the fresh duet them, a fruit and living objects being carried through closed windows and even solid brick walls. The scientific investigator naturally asks that an additional weight if it be only the 1,000th part of a grain be deposited on one pan of his balance when the case is locked. And the chemist asks for 1,000th part of a grain of arsenic to be carried through the sides of a gas tube in which pure water is hermetically sealed. These and other requirements are stated by Mr. Crooks together with further exposition of the principles of strict inductive investigation as it should be applied to such an inquiry. A year after this he published an account of the experiments which I described in a former letter and added to his own testimony that of the imminent physicist and astronomer Dr. Huggins and Sergeant Cox. Subsequently that is in the last number of the quarterly journal of science he has published the particulars of another series of experiments. I will not now enter upon the details of these but merely state that the conclusions of Mr. Crooks are directly opposed to those of the spiritualists. He positively, distinctly, and repeatedly repudiates all belief in the operations of the supposed spirits or of any other supernatural agency, whatever and attributes the phenomena he witnessed to an entirely different organ, Viz, to the direct agency of the medium. He supposes that a force analogous to that which the nerves convey from the ganglionic centers to the muscles in producing muscular contraction may be an effort of the will be transmitted to external inanimate matter in such a manner as to influence in some degree its gravitating power and produce vibratory motion. He calls this the psychic force. Speaking of the theories of the spiritualist Mr. Crooks in his first paper, July 1870 says the pseudoscientific spiritualist professes to know everything. No calculations trouble his serenity. No hard experiments, no laborious readings, no weary attempts to make clear in words that which has rejoiced the heart and elevated the mind. He talks glibly of all sciences and arts overwhelming the inquirer with terms like electrobiologies, psychologies, animal magnetism, et cetera. A mere play upon words showing ignorance rather than an understanding. And further on, he says, I confess that the reasoning of some spiritualists would almost seem to justify Faraday's severe statement that many dogs have the power of coming to more logical conclusions. I have already referred to the muddled misstatement of Mr. Crooks's position by the newspaper writers who almost unanimously describe him and Dr. Huggins as two distinguished scientific men who have recently been converted to spiritualism. The above quotations to which, if space permitted, I might add a dozen others from either the first, the second, or the third of Mr. Crooks papers in which he, as positively and decidedly controversy the dreams of the spiritualists will show how egregiously these writers have been deceived. They have relied very naturally on the established respectability of the quarterly review and have thus diluted both themselves and their readers. Considering the marvelous range of subjects these writers have to treat and the acres of paper they daily cover, it is not surprising that they should have been thus misled in reference to a subject carrying them considerably out of their usual track. But the offense of the quarterly is not so venial. It assumes, in fact, a very serious complexion when further investigated. The title of the article is spiritualism and its recent converts. And the recent converts, most especially and prominently named are Mr. Crooks and Dr. Huggins. Sergeant Cox is also named, but not as a recent convert for the reviewer describes him as an old and hopelessly infatuated spiritualist. Knowing nothing of Sergeant Cox, I am unable to say whether the reviewer's very strong personal statements respecting him are true or false, whether he really is one of the most gullible of the gullible, et cetera. Though I must protest against the bad taste which it displayed in the attack which is made upon this gentleman. The head in front of his offending consists in having certified to the accuracy of certain experiments and for having simply done this, the reviewer proceeds in accordance with the lowest tactics of Old Bailey's advocacy to bully the witness and to publish disparaging personal details of which he did 25 years ago. Dr. Huggins, who has had nothing further to do with the subject than simply to state that he witnessed what Mr. Crooks described and who has not ventured upon one word of explanation of the phenomena as similarly treated. The reviewer goes out of his way to inform the public that Dr. Huggins is, after all, only a brewer by artfully saying that like Mr. Whitbread, Mr. Lassel and other brewers we could name, Dr. Huggins attached himself in the first place to the study of astronomy. He then proceeds to sneer at such scientific amateurs by informing the public that they labor as a rule under a grave disadvantage in the want of that broad basis of scientific culture which alone can keep them from the narrowing and perverted influence of a limited specialism. The reviewer proceeds to say that he has no reason to believe that Dr. Huggins constitutes an exception to this rule and further asserts that he's justified in concluding that Dr. Huggins is ignorant of every other department of science and the small subdivision of a branch to which he has knew meritoriously devoted himself. Mark the words, small subdivision of a branch, merely a twig of the tree of sciences, according to the most unveracious writer, all that Dr. Huggins has ever studied. If a personal vindication were the business of this letter, I could easily show that these statements respecting the avocations, the scientific training and actual attainments of Dr. Huggins are gross and atrocious misrepresentations, but Dr. Huggins has no need of my championship. His high scientific position, the breadth and depth of his general attainments and the fact that he is not Huggins the Brewer are sufficiently known to all the scientific world with the exception of the quarterly reviewer. My objects is not to discuss the personal question whether bookmaking and dredging afford better or worse training for experimental inquiry than the marvelously exact and exquisitely delicate manipulations of the modern observatory and laboratory, but to protest against this attempt to stop the progress of investigation, to damage the true interests of science and cause of truth by throwing low libelous mud upon any and everybody who steps out all aside from the beaten paths of ordinary investigation. The true business of science is the discovery of truth, to seek it wherever it may be found, to pursue it through byways as well as highways and having found it to proclaim it plainly and fearlessly without regard to authority, fashion or prejudice. If however, such influential magazines as the quarterly review are to be converted into the vehicles of artful and elaborate efforts to undermine the scientific reputation of any man who thus does his scientific duty, the time for plain speaking and vigorous protest has arrived. The attack upon Mr. Crookes is still more malignant than that upon Dr. Huggins. Speaking of Mr. Crookes fellowship of the Royal Society, the reviewer says, we speak advisedly when we say that this distinction was conferred on him with considerable hesitation and further that we are assured on the highest authority that he is regarded among chemists as a specialist of specialists, being totally destitute of any knowledge of chemical philosophy and utterly untrustworthy as any inquiry which requires more than technical knowledge for its successful conduct. The italics in these quotations are my own, placed there to mark certain statements to which no milder term than that of falsehood is applicable. The history of Mr. Crookes admission to the Royal Society will shortly be published when the impudence of the above statements respecting it will be unmasked. And the other quotations I have emphasized are sufficiently and abundantly refuted by Mr. Crookes published works and his long and able conduct of the chemical news which is the only and the recognized British periodical representative of chemical science. If space permitted, I could go on quoting a long series of misstatements of matters of fact from the singularly unvaricious essay. The writer seems conscious of its general character for in the midst of one of his narratives he breaks out into a footnote stating that this is not an invention of our own but a fact communicated to us by a highly intelligent witness who is admitted to one of Mr. Crookes' seances. I have taken the liberty to emphasize the proper word in this very explanatory note. The full measure of the injustice of prominently thrusting forward Dr. Huggins and Mr. Crookes as recent converts to spiritualism will be seen by comparing the reviewer's own definition of spiritualism with Mr. Crookes' remarks above quoted. The reviewer says that the fundamental tenet of the spiritualist is the old doctrine of communication between the spirits of the departed and souls of the living. This is the definition of the reviewer and his logical conclusion is that Mr. Crookes is a spiritualist because he explicitly denies the fundamental tenet of spiritualism and Dr. Huggins is a spiritualist because he says nothing whatever about it. If examining the phenomena upon which the spiritualist builds his fundamental tenet and explaining them in some other manner constitutes conversion to spiritualism then the reviewer is a far more thoroughgoing convert than Mr. Crookes who only attempts to explain the mild phenomena of his own experiments while the reviewer goes in for everything including even the apotheosis of Mrs. Guppy and her translation through the ceiling a story which is laughed at by Mr. Crookes and everybody else accepting a few of the utterly crazed disciples of the lambs conduit mediums and the quarterly reviewer who actually attempts to explain it by his infallible and ever applicable psychological nostrum of unconscious celebration. No marvelous story either of ancient or modern date is too strong for this universal solvent which according to the reviewer is the sole and glorious invention of Dr. Carpenter. Space will not now permit me to further describe unconscious celebration and its vast achievements but I hope to find a corner for it hereafter. I may add that the name of the reviewer is kept a profound secret and yet is perfectly well known as everybody who reads the article finds it out when he reaches those parts which describe Dr. Carpenter's important physiological researches and discoveries. End of chapter 29, recording by Mickey Lee Rich.


Hello everyone, myself Sachin Rathod working in Department of Mechanical Engineering from Walsh Institute of Technology, Sallapur. Today we are dealing with the chapter that is the selection of the belt under the course of machine design one. So, the learning outcome of this session is student will able to design a V belt from manufacturing catalog. The numerical is it is required to design a V belt drive to connect a 7.5 kilowatt 1,440 rpm induction motor to a fan running at approximately 480 rpm for a service of 24 hours per day. The space is available for a center distance of about 1 meter. So, in these they had given us the power, the speed of the faster pulley and the speed of the smaller pulley and service for the working hour of the service that is the 24 hours per day as well as they had given us the center distance that is the 1 meter. So, these are the given data. So, the step number one we have to determine the correction factor according to the service. So, from this tables we have to find out the correction factor that is F A. So, as they had given us 7.5 kilowatt the speed of the faster pulley is 1,440 and the fan service is 24 hours per day. So, we are getting the F A is equal to 1.3. So, as the we are getting this for the 24 hours we are getting the service factor A is equal to F A is equal to 1.3. Step number two we have to find out the design power. So, we are knowing the equation design power is equal to F A into transmitted power as already we had calculated the value of F A that is the 1.3 and the transmitted power they had given us 7.5. So, you have to calculate the design power. So, it is coming at 9.75 kilowatt. Step number three determine the cross section of the belt based on design power and high speed of the shaft in rpm from the following table. So, in this table we have to find out the section of the belt as we are knowing there are the 5 section of the belts are available that is A, B, C, D, E. So, from that section belts we have to find out the appropriate cross section of the belt for the for our application. So, as they had given us the design power is 9.75 kilowatt. So, this horizontal axis indicating the line for the design power and the vertical axis is indicating for the speed of the faster shaft. So, as they had given us the design power is 9.75 kilowatt and speed of the faster pulley is 1440 rpm. So, this vertical line indicating the design power is 9.75 kilowatt just we are projecting this line and the speed of 1440. So, we have to project this line from 1440. So, it is going to intersect at this junction. So, the cross section of the belt is B belt. So, for the B belt we have to find out the recommanded minimum pitch diameter of the pulley. So, the belt section for our application is B belt. So, for that B belt the pitch width Wp is 14 mm this is Wp. The nominal top width W is equal to 17 mm. The nominal height is 11 mm t and the recommanded minimum pitch diameter is 200 mm. So, the value of small d is 200 mm. Just now we have to check out whether the 200 mm for the B section belt is available or not. Yes, it is available. Now, the step number 4 calculate the diameter of the bigger pulley as we are knowing the equation n1d is equal to n2d just put down the value of n1n2 as we are knowing the input speed and the output space as well as we have calculated the value of small d you have to find out the value of capital D. So, by putting this value we are getting the capital D is equal to 600 mm. So, again we have to check out whether the capital D 600 mm is available or not from the manufacturing data book. So, for the B section belt we have to check out 600 mm is available so we are getting capital D is equal to 600 mm. Step number 5 calculate the pitch length of the belt so as the application is for the open belt drive we have to select the equation for the open belt drive that L is equal to 2c plus pi in bracket d plus d divided by 2 plus d minus d bracket square divided by 4c. As we are knowing the value of centre distance between a two shaft and the diameter of smaller and the bigger pulley put this value you will get the answer L is equal to 3296.64 mm. Then the step number 6 select the standard pitch length so as this pitch length L is equal to 3296.64 mm we are getting by the calculation then we have to check out whether this pitch length is available or not so that data we are getting from the manufacturing data book. So, from this tables we have to check out whether that pitch length is available or not. So, for the B section belt it is not available so we have to select the pitch length as 3200 so we have selected the pitch length for the V belt is 3200 mm so now we have to find out the correct centre distance by considering the standard pitch length. So, you can think about this can we adjust the centre distance the answer is yes we can adjust the centre distance by approximate smaller value. So, in this equation we have to put the value of the standard pitch length and we have to calculate the C value. So, we are getting the C value is equal to 950.64 mm the previously in the example they had given us the centre distance is 1 meter approximately 1 meter they had given us. So, by considering the standard pitch length we are getting the distance between input shaft and output shaft is 950.64 mm. Step number 8 determine the correction factor of the belt pitch length that is indicated by the letter fc. So, we have to select the manufacturing catalog so from this catalogs we have to find out the value of fc so for the B section belts we are getting the standard pitch length as 3200 so we have to select the value of fc so we are getting the value of fc is 1.08 for the 3200 mm standard pitch length. Step number 9 calculate the angle of contact for smaller pulley that is indicated by the letter alpha s so we are getting this value alpha s is equal to 155.71 degree then step number 10 find the arc of contact factor fd from the manufacturing data as we are getting the value of wrap angle alpha s you have to calculate the value of fd so the value of alpha s is 155.71 so 155.71 it comes in between 154 and 157 so you are getting the value in between 0.93 to 0.94 so by using the trial method or interpolation method you are getting the value of fd is 0.9357 then step number 11 find the power rating pr from the manufacturing data so this table is indicating for the B section v belt so as they had given us the speed of the smaller pulley or the faster pulley is 140 rpm and the diameter is 200 mm for the B section so we have to find out the value of pr so the value of the speed of the faster shaft is 140 for diameter of the 200 so the pr value is 5.90 as well as we have to find out the speed ratio that is the speed of the faster pulley divided by the speed of the smaller pulley so we are getting the speed ratio is 3 so in the tables the speed ratio is 2 and over as we are getting the speed ratio is 3 so for the 1440 you are getting value as 0.46 so total pr value is equal to 5.90 plus 0.46 so we are getting the value as 6.36 kilo watt then step number 12 determine the number of the belt so as we are knowing this equation for finding the number of the belt calculate the number of the belt we are getting 1.51 so we have to consider the number of the belt required for that much power transmission is 2 belts so in this figures we have to use the 2 belt as we are getting the value of the diameter of the smaller pulley diameter of the larger pulley pitch length we are knowing center distance also we had calculated and number of the belt is 2 so at last the design solution will be obtained as the diameter of the smaller pulley small d is equal to 200 mm diameter of larger pulley capital D is equal to 600 mm belt specification is B3200 LP V belt the number of the belt required is equal to 2 center distance is equal to 950.64 mm so the reference I have taken as a VB Bhandari book