ISAAC NEWTON 107 



changing conditions in the ray which Newton dimly visual- 

 ised - but it has astonishing and unexpected peculiarities 

 (namely it is transverse and electromagnetic in character, 

 and not as Huygens first tried to regard it, longitudinal and 

 elastic). Nevertheless, this in no way contradicts the old 

 idea, which Newton also expresses in some places, of a 

 something projected with the velocity of light, inasmuch as 

 every wave is moving energy, and energy always possesses 

 both mass (inertia and also weight), quite as much as any 

 material body. How much more wonderful is nature than 

 we ever suspect before we come to know! All great men 

 of science have been sensible of this; we feel it in reading 

 their works. But most ordinary writers do not do them 

 justice. 



Newton's life history is quickly told.^ He was very 

 comfortable in England. He grew up under the care of his 

 mother and grandmother, since his father died before his 

 birth. He proved unfitted to look after the family estate; 

 but they were also not able to do much with him at school. 

 It was great good fortune that in spite of this, and apparently 

 ill-prepared, he was able to enter the University of Cam- 

 bridge at eighteen. His original tastes for mechanical 

 occupations, 2 for drawing, and for reading, then quickly 

 developed, by way of his mathematical studies, in the 

 direction where his lifework was to lie. He worked on his 

 own account on Descartes' geometry and Kepler's works; 

 Euclid soon appeared to him as self-evident. In this early 

 period also fall his own first experiments with the prism on 

 the nature of colours, his first ideas concerning gravitation, 

 and the beginnings of the calculus of fluxions, all of which 

 can be traced back to about the year 1666; they were then 



^ A biography of him by David Brewster appeared in 1831; see also the 

 works by S. Brodetsky and V. E. A. Pullin, both published in 1927 in 

 London. 



2 We are told of all kinds of mechanisms which he built, but which 

 were later all lost. 



