THE FORM AND CONSTITUTION OF THE EARTH. 
By Louis B. Stewart, D. T.S. 
The beginnings of astronomy probably date from the earliest 
development of the human intellect; and that it should be the oldest 
of the sciences need not be a matter for surprise when we consider 
the striking and interesting nature of its phenomena and the numerous 
services which it renders to mankind. Among the many questions 
requiring answers that would present themselves to a thoughtful 
observer possibly one of the first was that of the form and magnitude 
of our earth. 
To a spectator placed upon an eminence the earth, as far as it 
could be seen, appeared as a level plain, after making due allowance 
for minor inequalities, so that primitive man regarded the earth as 
flat, surrounded by an otherwise shoreless ocean. The sun at setting 
plunged beneath this ocean to reappear at the opposite side of the 
horizon at rising the following day. To allow for his passage beneath 
the earth it was conceived that the latter was supported by pillars 
between which the sun passed during his nightly journey. Thus the 
Greeks explained the motion of the sun, and they claimed that they 
were indebted to the Egyptians for their astronomical knowledge. 
The teaching of the Hindoos was even more fanciful than that of 
the Greeks. They taught that the earth is in the form of a hemi- 
sphere, resting with its flat surface on the backs of four elephants which 
in their turn stood upon the back of a gigantic tortoise. The question: 
What supports the tortoise ? received the answer: The endless ocean. 
The too curious inquirer who wished to know what supports the ocean, 
was met with the reply that it extends all the way to the bottom. 
As there is no statement that has come down to us concerning the 
nature of the bottom or to what it is indebted for its support, we must 
infer that the last answer stilled all further inquiry. 
Leaving these fanciful theories, we find that in comparatively early 
times more correct views as to the form of the earth were held by some 
philosophers, based no doubt upon the reports of phenomena observed 
by mariners and travelers, who found that the highest promontories 
disappeared from view as they drew away from the land; that a ship 
gradually vanished below the horizon in a manner that precluded the 
idea of a flat earth; that the sea horizon always appears circular. 
These and other phenomena, such as the varying meridian altitudes 
1 Retiring president’s address, annual meeting, Jan. 13. 1914. Reprinted by permission from the Journal 
of the Royal Astronomical Society of Canada, January-February, 1914. 
73176°—smM 1914 11 161 
