REPORT OF TEE CHEMIST 



191 



SESSIONAL PAPER No. 16 



twelve months. Further reference to the foregoing data shows that the rain falling 

 in September, October and November was particularly rich in ammonia. A very- 

 severe drought prevailed during August, September and the first three weeks of Octo- 

 ber, the rainfall being considerably below the average for these months. This exces- 

 sive dryness of the weather allowed the bush fires, which are not unusual at this time 

 of the year, to spread and gain very considerable headway. Fires were common not 

 only in the district known as the Ottawa Valley but also over large territories in 

 Ontario and Quebec and the northern part of New York State. These fires raged 

 almost, continually, the rainfalls being very light for many weeks, so that for two 

 months, more or less, the atmosphere was heavily charged with smoke. Hundreds of 

 acres of forest were burnt and thousands of dollars worth of timber destroyed. So 

 dense was the smoke at times that for several days together at Ottawa it was difficult 

 to see clearly for many yards, and the irritation to the eyes and mucous membrane 

 of the nose and throat was excessive. Not until the heavy rain of the 24;th and 25th 

 of October was the atmosphere again cleared. This smoke naturally contained large 

 proportions of ammonia as a product of combustion, and hence the scanty precipita- 

 tions that occurred during these weeks were exceptionally rich in that constituent. 

 To this cause then we attribute the exceptional and phenomenally high results re- 

 corded in the table. 



A further disturbing factor that we observed was the high winds that prevailed 

 from time to time, immediately before or during the early part, of a rain and when the 

 surface soil was dry. This happened repeatedly last year, both in the spring and 

 summer months, and especially did we remark instances during April and June. 

 Severe thunderstorms, almost cyclonic in their violence, are by no means uncommon 

 at Ottawa during the hot months, and it frequently happens that the rain is then pre- 

 ceded by a wind which may reach the velocity of a hurricane. As such usually occur 

 after .a period of longer or shorter drought, when the surface of the cultivated fields is 

 dry and loose, the air is filled with particles of organic matter, manure and debris of 

 various kinds. Naturally the rain falling through such an atmosphere has its nitrogen 

 content very greatly increased. Unfortunately there seems to be no plan or method 

 whereby this source of error can be eliminated or avoided, and it is quite possible that 

 a part of tha larger amount of nitrogen, recorded for the past year, is due to the 

 greater frequency of such winds during periods of dryness last summer. 



Of the total amount of nitrogen, 8-364 lbs., 84 per cent, or 7-026 lbs., occurred 

 as free and organic ammonia, and 16 per cent, or 1-338 lbs., as nitrates and nitrites. 



The nitrogen furnished by the rain was estimated at 90 per cent of the whole, or 

 7-528 lbs. per acre; that by the snow at 10 per cent, or -836 lbs. per acre. 



The average nitrogen-content of the rain and of the snow is set forth in the 

 following table : — 



Average Nitrogen Content of Rain and Snow — Amount of Nitrogen, per Acre, as 

 Free and Albuminoid Ammonia and as Nitrates and Nitrites. 



