11^ 



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

 pearance and of most amiable character; and his body was followed 

 to the grave, with every manifestation of respect and affectionate at- 

 tachment, by the whole body of the pupils and professors of the 

 institution of which he had so long been a principal ornament. 



Dr. William Ritchie was originally Rector of the Roj-al 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 anew Photometer," " On a 

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

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

 which led to his appointment, through the recommendation of Major 

 Sabine, to the Professorship of Natural Philosophy at the Royal In- 

 stitution, where he delivered a course of probationary lectures in the 

 spring of 1829 : he became, from this time, a permanent resident in 

 London, and was appointed to the Professorship of Natural Philo- 

 sophy at the London University in 1832. He subsequently commu- 

 nicated to the Royal Society, papers " On the Elasticity of Threads 

 of Glass, and the application of this property to Torsion Balances ;" 

 and also various experimental researches on the electric and che- 

 mical theories of galvanism, on electro-magnetism and voltaic elec- 

 tricity, which are more remarkable for the practical ingenuity mani- 

 fested in the contrivance and execution of the experiments, than for 

 the influence of the views which they display on the progress of their 

 theory, which was so fully and so happily developed by the cotem- 

 porary labours of another illustrious chemist and philosopher. 

 Dr. Ritchie was subsequently engaged in experiments, on an exten- 

 sive scale, on the manufacture of glass for optical purposes, for the 

 examination of the results of which a Commission was appointed by 

 the Government, with a vicM' to their further prosecution by a public 

 grant of money, or by affording increased facilities of experiment by 

 a relaxation of the regulations of the Excise. A telescope of 8 inches 

 aperture was made by Mr. DoUond from Dr. Ritchie's glass, at the 

 recommendation of this commission ; but it is generally understood 

 that its performance vras not so satisfactory as to sanction a further 

 expenditure in the extension of these experiments. Dr. Ritchie died 

 in the autumn of the j)resent year, of a fever caught in Scotland ; 

 and though the traces of an imperfect and irregular education are 

 but too manifest in most of his theoretical researches, yet he must 

 always be regarded as an experimenter of great ingenuity and 

 merit, and as a remarkable example of the acquisition of a very 

 extensive knowledge of philosophy under difiiculties and privations 



