Aniizversar?/ of IS3^, Address of the President 275 



mathematician of no inconsiderable attainments, a very careful and 

 efficient practical astronomer, and admirably qualified for the very 

 important and responsible duties which he was appointed to dis- 

 charge. 



Dr. Edward Turner was a native of Jamaica, and studied medi- 

 cine at Edinburgh, and chemistry at Gottingen under the instruc- 

 tions of the celebrated analytic chemist Stromeyer. He became a 

 lecturer on chemistry at Edinburgh in 1824, and his first publica- 

 tion was a short introduction to the study of the laws of chemical 

 combination and the atomic theory. He obtained the Professorship 

 of Chemistry in the London University at its first establishment in 

 1 828, a situation which he continued to hold to the end of his life. 

 His Elements of Chemistry have enjoyed an uncommon degree 

 of popularity, and are remarkable for clearness and precision both 

 in the description of his experiments and in the deduction of 

 his theory*. He was the author of two papers in our Transactions ; 

 the first "On the Composition of the Chloride of Barium," and the 

 second containing " Researches on Atomic Weights," both written 

 with a view of impugning the theory which had been promulgated by 

 some English chemists of high authority, " that all atomic weights 

 are simple multiples of that][of hydrogenf ." In the year 1835 Dr. 

 Turner was compelled by the declining state of his health to suspend 

 all original researches, confining himself simply to the duties of his 

 professorship ; and he died in February last, in the fortieth year of 

 his age, to the deep regret of every friend of the progress of chemi- 

 cal science. He was a person of most engaging manners and ap- 

 pearance and of most amiable character; and his body was fol- 

 lowed to the grave, with every manifestation of respect and affection- 

 ate attachment, by the whole body of the pupils and professors 

 of the institution of which he had so long been a principal orna- 

 ment. 



Dr. William Ritchie was originally Rector of the Royal Academy 

 of Tain in Inverness-shire, where he contrived, by extreme frugality, 

 to save a sufficient sum from his very small annual stipend to attend 

 a course of the lectures of Thenard, Gay-Lussac, and Biot at Paris, 

 and also to provide a substitute for the performance of his duties 

 during his temporary absence from Scotland. His skill and ori- 

 ginality in devising and performing experiments with the most simple 

 materials, in illustration of various disputed points of natural phi- 

 losophy, attracted the attention of the distinguished philosophers 

 whose occasional pupil he had become : he had also communicated, 

 through Sir John Herschel, who took a strong interest in his for- 

 tunes, to the Royal Society, papers " On a new Photometer," " On a 

 new form of the Differential Thermometer," and " On the Permea- 

 bility of transparent Screens of extreme tenuity by Radiant Heat," 



* This work was reviewed in Phil. Mag. and Annals, N.S., vol. L p. 

 379. 



t Dr. Turner's paper on the chloride of barium was given in Phil. Mag. 

 and Annals, N.S., vol. vHi. p. 180 ; and abstracts of his Researches on 

 atomic weights in L, & E. Phil. Mag., vol. i, p. 109; iii, p. 448. 



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