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THE ROYAL SOCIETY OF CANADA 



probably contributes a small quota of ammonia and atmospheric 

 electricity discharges furnish a further small amount of nitrates. 

 In addition to the gaseous compounds, there is also present in the air, 

 in small proportions, organic matter containing nitrogen, due to dust, 

 soot and other small and suspended particles, and this nitrogen as 

 washed out by the rain and snow has been estimated and recorded 

 by the writer as albuminoid ammonia. 



This examination, conducted at the Central Experimental Farm, 

 situated just outside the limits of the City of Ottawa, is now in its 

 eighth year and the purpose of this paper, which is practically a 

 report of progress, is to give a summary of the results to the close 

 of the seventh year, February 28th, 1914. 



In the following table the precipitation data and the amounts 

 of nitrogen furnished annually per acre for the experimental period 

 are given. 



Precipitation and Amount of Nitrogen per acre, Ottawa, Ont., 1908-1914. 



The average annual precipitation at Ottawa, as calculated for 

 the experimental periods employed in this work, for the past 23 years 

 from the meteorological records of the Farm, is 34-34 inches, 25-14 

 inches falling as rain and 9-20 (snowfall = 92 • 03 inches) as snow. 

 In three years of the seven the precipitation has not reached and in 

 four years it has exceeded, the average. The largest variations are 

 to be noted in the year ending February, 1911, with a precipitation 

 of 7-37 inches below the average and in the year closing February, 

 1913, when the precipitation exceeded the average by 5-62 inches. 

 The variations in the annual snowfalls are, as might be expected, 

 much greater than those of the rainfalls. 



With respect to the total nitrogen, as recorded in pounds per 

 acre, the amounts for four of the yearly periods are practically identi- 

 cal, and very close to the average for the seven years, viz., 6- 182 lbs. 



