Section III., 1894. [ 47 ] Trans. Rot. Soc. Canada. 



V. — Some OhserKations on tlic Qualif// of the Air at Ottaioa. 

 By Frank T. Shdtt, M.A., F.I.C., and A. McGill, B.A., B.Sc. 



(Comniunicated by Mr. Macfarlane and read May 25, 1894.) 



Some time ago the authors undertook at the instance of the Department of Puhlic 

 Works the examination of the air of the House of Commons Chamber at Ottawa. Tliis 

 work was continued over a period of two weeks during session. The amounts of carbonic 

 acid and moisture present were estimated in the centre of the Chamber, the apparatus 

 employed being arranged on tlie table of the House. As this investigation is as yet unfinished 

 and the interim results have not been published, it is not our intention in this paper to state 

 the data obtained in that examination, but rather to place on record the figures resulting 

 from several analyses of the air upon Parliament Hill, made for the purpose of comparison 

 and the establishment of a standard of purity. 



The hygienic condition of air is, for practical purposes, generally diagnosed from the 

 amounts of carbonic acid and moisture it contains — and more especially from the former. 

 These are the products of combustion and respiration, and are comparatively easy of deter, 

 mination. Carbonic acid, unless in vei-y large amounts, may not, in itself, prove injurious to 

 health Imt, when it is the product of respiration, it is always accompanied hy organic 

 impurities (the result of waste tissue, &c.) which are exceedingly deleterious. The amount 

 of carbonic acid under the circiimstances just mentioned is, therefore, a measure of the 

 vitiating impurities. 



Carbonic acid is always present as a normal constituent in pure air. Its amount in such, 

 however, is always within certain narrow limits, to establish which for Ottawa during the 

 time of the analyses before referred to, the results here given- were obtained. 



It has been customary to quote four volumes per 10,000 as the normal (piantitv of car- 

 bonic acid in pure air. Recent work by Thorpe (Chem. Soc. Journ., XX., 189) has shown 

 that air resting on the sea contains about three volumes per 10,000. M. Marie-Davy at the 

 Montsouris Observatory, situated in the suburbs of Paris, has made a series of observations 

 extending over nine years and including more than 3,000 analyses, and gives as tlie annual 

 mean for the nine years 2-96 volumes per 10,000. It is, however, probable that this result 

 is slightly too low, owing to imperfect absorption of the carbonic acid in the process employed. 

 M. Marie-Davy causes the air to pass through the absorbing fluid at the rate of 10,000 cubic 

 feet per hour. Mr. E. M. Dixon, B. Sc, who has made a very large number of analyses in 

 the neighbourhood of Glasgow, Scotland, transmits the air at the rate of one cubic foot per 

 hour, and finds an average of 3-04 volumes per 10,000. (Fox, page 230, Churchill, 1886). 



Dr. Angus Smith found in the suburbs of Manchester, as the result of fourteen analyses, 

 3-69 volumes per 10,000, and in the streets of London, England, in summer 3-80 volumes 



