XXXV 



Mr. Perkins's Account of the Compressibility of Water," in the 'Annals of 

 Philosophy,' N. S. vol. i. p. 135 ; and in 1822, a Biographical Memoir of 

 his valued friend and frequent fellow-worker Dr. Alexander Marcet, in the 

 'Annals of Biography and Obituary' for 1823. In 1823 he is quoted by 

 Dr. Cooke in his work on Epilepsy, pp. 147, 151, & 215. On the 1st 

 of May in the same year he was appointed Physician to the General Peni- 

 tentiary, Milbank, in conjunction with Dr. P. M. Latham, on the occasion 

 of an epidemic dysentery which prevailed among the prisoners. His 

 labours there occupied him for fifteen months ; and in 1824 appeared the 

 joint report of himself and his colleague to the House of Commons. In 

 the autumn of that year was another great epoch of his life, namely that of 

 his marriage. 



Dr. Roget married Miss Hobson, only daughter of Mr. Jonathan Hob- 

 son, a merchant of Liverpool. The union was one of unclouded happiness, 

 but of short duration. Mrs. Roget, after giving birth to a daughter and 

 a son, died in the spring of 1833, of a lingering disease. 



On the 9th of December, 1824, another mathematical paper of Dr. Ro- 

 get's was read at the Royal Society; this is entitled "An Explanation of 

 an Optical Deception in the appearance of the Spokes of a Wheel seen 

 through vertical apertures" (Phil. Trans, for 1825, p. 131) ; and in 1825 

 he wrote another in the 'Scientific Gazette,' Nov. 5 and 12, "On an ap- 

 parent violation of the Law of Continuity." In 182G, besides his "Intro- 

 ductory Lecture," there appeared an article by him on Electro-Magnetism 

 in the ' Quarterly Review,' being a review of Ampere's ' Recueil d'Obser- 

 vations Electro-Dynamiques,' and Barlow's 'Essay on Magnetic Attrac- 

 tions;' and an article "On the Quarantine Laws," in the Parliamentary 

 Review, p. 785. 



In 1827 he received a commission, with Mr. Telford and Mr. Brande, 

 under the Great Seal, to inquire into the supply of water to the Metropolis, 

 which resulted in the publication of their report in 1828. 



He began at this time the composition of the series of treatises in the 

 ' Library of Useful Knowledge' on "Electricity, Galvanism, Magnetism 

 and Electro-Magnetism." They were issued in parts in the years 1827 

 1829, and 1831, aud were afterwards published together in one volume. 

 These treatises were held in considerable repute at the time they were pub- 

 lished, and that on Electricity reached a second edition. He also wrote 

 the article Galvanism in the 'Encyclopaedia Metropolitana.' His con- 

 nexion with the Society for the Diffusion of Useful Knowledge, for which 

 the above treatises were written, is thus referred to by Mr. Charles Knight, 

 in his ' Passages of a Working Life ' : — " x\mongst the founders of this 

 Society, Dr. Roget was, from his accepted high reputation, the most emi- 

 nent of its men of science. He was a vigilant attendant on its committees ; 

 a vigilant corrector of its proofs. Of most winning manners, he was as 

 beloved as he was respected Upon all questions of Physiology, Peter 



vol. xviii. e 



