THE RENAISSANCE OF SCIENCE. 25 



tight within a wheelwork of revolving spheres. It was compendious, 

 complete, ingenious, like a toy in a crystal box. Beyond the outer shell 

 nothing existed. The heavens were incorruptible. No change could 

 occur in the whole system, save on the earth alone. The universe was 

 created for the sole use of man. It was small and finite. To us, the 

 awful infinitudes of space are only to be faintly imagined after a series 

 of conceptions, each one so overwhelming that it fades after the briefest 

 instant of realization. Human attention can not grasp the whole series 

 in one view. Each one of the myriad stars is a sun like our own, sub- 

 jected, as it is, to prodigious physical alterations and catastrophies. 

 Each one is, perhaps, surrounded by a train of planets, like those we 

 know, that must forever remain invisible to our vision. The condition 

 of every celestial body is perpetually changing in a long progress of 

 evolution. Each separate star is situated as far from every other as 

 our own sun from the very nearest of them all. Every star is in 

 motion. The sun, so mighty and all-powerful to us, is but a feeble 

 light among thousands of millions of others scattered so sparsely 

 throughout the never-ending expanse that centuries are needed even 

 for their light to traverse the intervening spaces. In the feeble light 

 of that sunbeam, vital to us, the earth, our mother, shines like the 

 merest mote. Its past is limited, its future insecure. With its finite 

 history the fate of mankind is bound up. 



We must not forget that the modern view of the universe is very 

 different from that of Copernicus. Before his day the earth was mo- 

 tionless in the center of the world. After it the earth was in perpetual 

 motion about the sun. Copernicus conceived the sun as fixed. But 

 under Newton's law of universal gravitation there can be no fixed 

 bodies. All are in motion. Our sun with its train of planets is 

 speeding through space towards a goal as yet unknown. Newton's law 

 of gravitation banished rest from the universe. To Copernicus as to 

 Ptolemy rest was the natural state to which all bodies tended. They 

 moved only when perpetually urged. The science of mechanics 

 founded by Galileo and Newton changed all this. The real reformation 

 of science dates from the acceptance of the new conception. 



