OF ROBERT ANGUS SMITH. 95 



one entitled " Some Remarks on the Air and Water of 

 Towns/' published in the Chemical Society's Journal, 

 1845-48. His results are summed up in an independent 

 work entitled '^Air and Rain/ and published in 1872. 

 Much o£ Dr. Smith's work was necessarily of a purely 

 qualitative character, for the phenomena which he inves- 

 tigated are concerned with almost infinitesimal quantities 

 of matter. Nevertheless, whenever it was possible, he 

 introduced quantitative methods, as when examining the 

 amount of acid contained in the atmosphere, of which 

 an account will be found in his paper " On Minimetric 

 Analysis," read before this Society in the Session 1865-66. 

 This paper contains a description of a very simple and 

 ingenious little apparatus, called by him a " finger-pump," 

 by which the amount of impurity in the atmosphere, in 

 the shape of carbonic acid or hydrochloric acid, can be 

 rapidly and easily determined. On disinfectants, to which 

 Dr. Smith's attention was naturally directed, he worked 

 much, his general views on the subject being contained in 

 a separate work published in 1869, and entitled 'Disin- 

 fectants and Disinfection.' The practical result of his 

 studies in this direction was the invention of a very useful 

 disinfectant, which was introduced by Mr. McDougall, and 

 is still largely employed. This short resume may perhaps 

 suffice to give some idea of Dr. Smith's labours on air 

 and water in their hygienic relations ; but before closing it 

 some allusion should be made to his able report '' On the 

 Air of Mines," chiefly those of Cornwall, presented to 

 Government, by whose directions the inquiry into the 

 atmospheric conditions prevailing in mines was under- 

 taken. Dr. Smith's memoirs on purely scientific subjects 

 are not numerous. Among them may be mentioned those 

 on rosolic acid, on the absorption of gases by charcoal, 

 which he supposed to take place in certain definite propor- 



