A table, comprising the numerical elements of the planets
(that is to say, their mean distances fi:om the Sun, sidereal
periods of revolution, the eccentricity of their orbits, their in-
clination toward the ecliptic, their diameter, nrass, and dens-
ity), would now embrace within very narrow limits the rec-
ord of the great intellectual conquests of the present age. Let
us for a moment transport ourselves in imagination to the
times of the ancients, and fancy Philolaiis the, Pythagorean,
the instructor of Plato, Aristarchus of Samos, or Hipparchus,
in possession of such a numerical table, or of a graphic rep-

* On the appearance of new stars, and their subsequent disappear
ince, see p. 151-164.
THE SOLAR REGION. bl

resentation of the orbits of the planets, such as is given in
our most epitomized manuals, there is scarcely any thing tc
which we could compare the admiration and surprise of these
men — the heroes of the early and limited knowledge of that
age — excepting, perhaps, that which might have been expe-
rienced by Eratosthenes, Strabo, and Claudius Ptolemy, could
they have seen one of our maps of the world, on Mercator'a
projection; not above a few inches in length and breadth.
