NICOLAUS COPERNICUS 23 



THAT THE UNIVERSE IS SPHERICAL 



First we must remark that the universe is spherical in form, partly 

 because this form being a perfect whole requiring no joints, is the 

 most complete of all, partlybecause it makes the most capacious form, 

 which is best suited to contain and preserve everything; or again 

 because all the constituent parts of the universe, that is the sun, moon, 

 and the planets appear in this form ; or because everything strives to 

 attain this form, as appears in the case of drops of water and other 

 fluid bodies if they attempt to define themselves. So no one will doubt 

 that this form belongs to the heavenly bodies. 



THAT THE EARTH IS ALSO SPHERICAL 



That the earth is also spherical is therefore beyond question, be- 

 cause it presses from all sides upon its center. Although by reason of 

 the elevations of the mountains and the depressions of the valleys a 

 perfect circle cannot be understood, yet this does not affect the gen- 

 eral spherical nature of the earth. This appears in the following 

 manner. To those who journey towards the North the north pole of 

 the daily revolution of the heavenly sphere seems gradually to rise, 

 while the opposite seems to sink. Most of the stars in the region of 

 the Bear seem not to set, while some of the southern stars seem not to 

 rise at all. So Italy does not see Canopes which is visible to the 

 Egyptians. And Italy sees the outermost star of the Stream, which 

 our region of a colder zone does not know. On the other hand to 

 those who go towards the South the others seem to rise and those 

 to sink which are high in our region. Moreover, the inclination of 

 the Poles to the diameter of the earth bears always the same relation, 

 which could happen only in the case of a sphere. So it is evident that 

 the earth is included between the two poles, and is therefore spherical 

 in form. Let us add that the inhabitants of the East do not observe 

 the eclipse of the sun or of the moon which occurs in the evening, and 

 the inhabitants of the West those which occur in the morning, while 

 those who dwell between see those later and these earlier. That the 

 water also has the same form can be observed from ships, in that 

 the land which cannot be seen from the deck, is visible from the mast- 

 tree. And conversely if a light be placed at the mast-head it seems 



