276 Royal Society. 



whiqh 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 contem- 

 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 view 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 was not so satisfactory as to sanction a further 

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

 in the autumn of the present 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 difficulties and privations 

 which would have arrested the progress of any person of less ardour 

 and determination of character*. 



Mr. Joseph Sabine was educated in the University of Dublin, 

 and devoted himself, from a very early period of life, to the study 

 of botany, ornithology, and other branches of natural history, to the 

 neglect of those professional studies which his friends designed him 

 to pursue. One of 'his earliest labours was the formation of a col- 

 lection of British birds of almost unrivalled extent and completeness. 

 He became secretary to the Horticultural Society at the period of 

 its first establishment ; and though his connection with it was after- 

 wards very abruptly and perhaps very harshly terminated, he must 

 always be considered as the chief author of its successful and com- 

 plete development. To the Horticultural Transactions he contri- 

 buted 64 papers, the most important of which are those on the ge- 



• Abstracts of Dr. Ritchie's papers read before the Royal Society will 

 be found in Phil. Mag. and Annals, N.S., vol. vi. p. 52 ; viii. 58 ; x. 226; 

 xi. 448; and L. & E. Phil. Mag., vol. iii. pp. 37, 145 ; x. 220; xi. 192. 

 Papers communicated by him to the Philosophical Magazine have appeared 

 in nearly every volume of the present series. 



