BIOGRAPHICAL INDEX 



(The matter under this alphabet constitutes at once a 

 Biographical Reference Index and a condensed Bio- 

 graphical Dictionary of the Important names in every 

 department of science. The figures following the names 

 refer to the text by volume and page. The reading mat- 

 ter is complementary to the matter of the Technical 

 Index and Glossary, and of the General Index, and to 

 some extent supplementary of the text itself.) 



Abd-el-Letif, or Abd-ul-Latif, ii, 21. Born at 

 Bagdad, 1162; died at Bagdad, 1231. Arabian 

 scholar and author of multifarious acquirements. 

 He labored unceasingly in his early years to 

 acquire all the knowledge of his age. 

 Lived at Damascus and spent many years in 

 Egypt, of which country he has left an excellent 

 and accurate account. Devoted much time to 

 study of medicine. 



Adams, John Couch, iii, 42, 48. Born at Corn- 

 wall, England, 1819; died at Cambridge, 1892. 

 At an early age he displayed a great aptitude 

 for mathematics and became a mathematical 

 tutor at Cambridge. In 1841 he set himself to 

 the task of discovering the cause of the irregu- 

 larities in the motion of the planet Uranus, and 

 in October, 1844, wrote an account of the exist- 

 ence of a new planet and gave its location. This, 

 unfortunately, he did not publish. Leverrier, in 

 France, took up the same subject in 1845, anc ^ 

 announced the existence of Neptune in Novem- 

 ber of that year. Hence he obtained the whole 

 honor of the discovery, which Adams should 

 have shared. In 1858 Adams was appointed pro- 

 fessor of mathematics at St. Andrews, Cam- 



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