Section III, 1917 [63] Trans. R.S.C. 



The Nitrogen Compounds in Rain and Snow. 



By Frank T. Shutt, M .A., D.Sc, and R. L. Dorrance, B.A. 

 (Read May Meeting, 1917.) 



The determination of the nitrogen compounds in rain and snow- 

 has been the subject of considerable investigational -work, the enquiry 

 having been prosecuted in recent years in almost every country where 

 chemistry and agriculture are scientifically studied. Dr. N. H. J. 

 Miller in his paper entitled "The Composition of Rain-water collected 

 in the Hebrides and in Iceland" (The Journal of the Scottish Meteoro- 

 logical Society, Vol. XVI, No. XXX) quotes results from about sixty 

 stations experiencing a variation in annual precipitation of from 15 to 

 75 inches and scattered over the civilized world. The investigation 

 in some instances had been carried on over a considerable period. 



Miller points out that as early as 1870, R. Angus Smith in his 

 paper entitled "Chemical Climatology" (Journal Scottish Meteor- 

 ological Society, 1870, 3. 2-11) discussed the analysis of air and rain- 

 water collected in towns and rural districts and showed the contamina- 

 tion of the air by cities and thickly populated areas. In the seven- 

 teenth and eighteenth centuries the fertilizing value of rain, snow 

 and dew was recognized by agricultural writers. Hjarne (Acta et 

 Tentamina Chemica Holmiensia, sect, ii., p. 23, Stockholm, 1753) 

 mentions the analyses of rain-w^ater as made by Borrichius of Copen- 

 hagen, 1674, which appear to be the first recorded. 



The work here reported is a Canadian contribution to this en- 

 quiry; and constitutes a review of the first decade's work^ It was 

 begun in 1907, and has had for its chief object the determination of 

 the amounts of the several nitrogen compounds furnished, per acre, 

 annually to the soil by the rain and snow as falling in the neighbor- 

 hood of Ottawa. The work has included the estimation of the various 

 combined forms, free ammonia, albuminoid ammonia and nitrates 

 and nitrites. Incidentally, a study has been made of the factors 

 which influence the nitrogen concentration of the various precipita- 

 tions. The fact that the samples of snow, when collected, appeared 

 spotlessly white, but on melting gave varying amounts of black 

 deposit in the containing vessel indicates that the falling of the snow, 



1 Interim reports on this investigation were presented to this Society in 1910 

 and 1914 (Trans. R.S.C. Vol. IV and Vol. VIII, Third Series.) 



