ROTUNDITY OF THE EARTH. 17 



out, for he himself did not live to witness the complete triumph 

 of his bold attempt. Magellan was a Portuguese who had entered 

 into the service of Spain. In the year 1519 he sailed for South 

 America, and discovered the straits called by his name, and 

 which separate the island of Terra del Fuego from the continent. 

 He likewise discovered the Marian and Phillipine islands, which 

 _he took possession of in the name of the King of Spain, and was 

 killed on one of the latter group. His fleet was mostly dispersed, 

 but one ship with eighteen men, returned'to Spain in 1522, having 

 sailed westward completely around the world. The rotundity of 

 the earth, by these means, was established beyond a doubt, though 

 indeed this proof was not necessary, a great variety of phenomena 

 giving the same result. For example, the shadow of the earth, 

 which is cast upon the moon at the time of a lunar eclipse, is 

 always bounded by a curved line or circle, and it can be shown 

 mathematically, that a spherical form is absolutely necessary for 

 the stability of the earth. The moon, and all the planetary bodies, 

 are also observed to present discs, the same as a ball suspended in 

 the sky. Having learned these two things, viz : that there is a 

 great and unceasing motion somewhere, and that the earth is 

 j-ound, it becomes interesting to determine its actual size, its 

 diameter and circumference. Previous to determining this and 

 on the supposition that our earth is the grand centre of the uni- 

 verse, let us study the phenomena presented by the sun, plan- 

 ets, and stars in their apparent diurnal or daily revolution around 

 the earth, premising however, that to certain directions upon its 

 surface the arbitrary names, North, South, East, and West, have 

 been assigned. For example, we call the part towards the north 

 star north, the opposite south, and facing towards the north star, 

 we call the right hand east, and the left hand west. These names 

 are entirely arbitrary, i. c., they do not actually represent fixed 

 directions in space, but are simply relative expressions, thus, what 

 is east to one observer, may be west to another, for example, take 

 the next diagram, representing the earth as round, the north pole 

 being at the position N, and suppose two observers one at A, and 

 the other at B, both facing towards the north. 



If questioned about some object C, B would declare it to be 



