The writer of these lines takes this opportunity of recording his own 

 deep debt of gratitude to Dr. Frost. Some four years ago, when the 

 writer ceased to be able to read, Dr. Frost with characteristic kindness 

 and generosity volunteered to act as reader. His readings, which took 

 place three or four times a week, and lasted about an hour and a half 

 each, were continued until Dr. Frost was attacked by his fatal illness. 

 In that period something like thirty octavo volumes, on subjects of 

 diverse interest, were read, as well as a sprinkling of special articles 

 from the ' Times,' or papers in ' Nature ' and other scientific peri- 

 odicals. 



The memory of such a friend cannot easily fade. 



H. M. T. 



LYON PLAYFAIR, son of Dr. George Playfair, Chief Inspector 

 General of Hospitals, Bengal, was born at Meerut, May 21, 1819. 

 He came home for his education to St. Andrews, where his grandfather- 

 had been Principal of the United College of St. Salvator and St. 

 Leonard, and where his uncle, Sir Hugh Lyon Playfair, after a dis- 

 tinguished career in the Indian army, retired in 1834, not to repose but 

 to new battles against dirt, disorder, arid ruin, battles the result of 

 which we see in the clean, prosperous, and healthy city of St. Andrews. 

 We may well believe that Lord Playfair derived some of his enthu- 

 siasm for sanitation and order from this uncle, "the eccentric and 

 energetic soldier who begged and bullied and wheedled away the filth 

 and ruinous neglect which bade fair to entomb the ancient city." 

 After some years in St. Andrews, he went to Glasgow to study 

 medicine, but was attracted to chemistry by the teaching of Thomas 

 Graham, then Professor of Chemistry in the Andersonian. After a 

 short visit to India he resumed his chemical studies, under Graham, in 

 the University College, London. In 1838 he went to Liebig's labora- 

 tory at Giessen, where he worked at organic chemistry and produced 

 his first scientific paper " On a new Fat Acid in the Butter of Nut- 

 megs." Liebig was not only his teacher but his friend, and when 

 Liebig, on the invitation of Prince Albert, came to this country to 

 lecture on agricultural chemistry, Playfair acted as his assistant and 

 interpreter, and was thus introduced to the Prince, an introduction 

 which had an important effect on his subsequent life. 



For two years he managed the chemical department of Messrs. 

 Thomson's print-works, at Clitheroe. In 1843 he was appointed Pro- 

 fessor of Chemistry in the Koyal Institution, Manchester. In 1844, 

 on the recommendation of Sir Robert Peel, he was appointed a member 

 of a Royal Commission for the examination of the sanitary condition 

 of large towns and populous districts. This was the beginning of what 

 was to be a large part of the work of his life. In 1845 he was one of 

 the commissioners on the Irish famine, and from that time till his death 



