CH. ix., 164-168] Newton's Early Life 211 



some unsuccessful attempts to turn him into a farmer^he 

 was entered at Trinity College, Cambridge, in 1661. 



Although probably at first rather more backward than 

 most undergraduates, he made extremely rapid progress 

 in mathematics and allied subjects, and evidently gave his 

 teachers some trouble by the rapidity with which he 

 absorbed what little they knew. He met with Euclid's 

 Elements of Geometry for the first time while an under- 

 graduate, but is reported to have soon abandoned it as 

 being " a trifling book," in favour of more advanced reading. 

 In January 1665 he graduated in the ordinary course as 

 Bachelor of Arts. 



1 66. The external events of Newton's life during the 

 next 22 years may be very briefly dismissed. He was 

 elected a Fellow in 1667, became M.A. in due course in 

 the following year, and was appointed Lucasian Professor 

 of Mathematics, in succession to his friend Isaac Barrow, 

 in 1669. Three years later he was elected a Fellow of the 

 recently founded Royal Society. With the exception of 

 some visits to his Lincolnshire home, he appears to have 

 spent almost the whole period in quiet study at Cambridge, 

 and the 1m t >ry of his life is almost exclusively the history 

 of his succ.es ,ive discoveries. 



167. His scientific work falls into three main groups, 

 astronomy (including dynamics), optics, and pure mathe- 

 matics. He also spent a good deal of time on experimental 

 work in chemistry, as well as on heat and other branches 

 of physics, and in the latter half of his life devoted much 

 attention to questions of chronology and theology ; in none 

 of these subjects, however, did he produce results of much 

 importance. 



1 68. In forming an estimate of Newton's genius it is of 

 course important to bear in mind the range of subjects 

 with which he dealt ; from our present point of view, how- 

 ever, his mathematics only presents itself as a tool to be 

 used in astronomical work ; and only those of his optical 

 discoveries which are of astronomical importance need be 

 mentioned here. In 1668 he constructed a reflecting 

 telescope, that is, a telescope in which the rays of light from 

 the object viewed are concentrated by means of a curved 

 mirror instead of by a lens, as in the refracting telescopes 



