[sHUTT-DORRANCE] NITROGEN COMPOUNDS IN RAIN AND SNOW 69 



satisfactorily explain this apparently abnormal condition of the 

 precipitation. 



While as already pointed out the volume of precipitation must 

 in some degree determine the amount of nitrogen annually furnished, 

 the results have not shown any direct relation between the annual 

 precipitation and pounds of nitrogen per acre. The precipitation 

 varies from 25-3 to 39-9 inches within the decade, but if we 

 except the three apparently abnormal years referred to, the number 

 of pounds of nitrogen furnished per acre is a fairly constant 

 quantity. 



The widest variations are to be found in the nitrogen as free 

 ammonia ; the most constant determination is that recorded as 

 albuminoid ammonia. 



Table II. This table is a record of the precipitation in inches, 

 nitrogen content and pounds of nitrogen per acre, by months, for 

 the decade. 



The August precipitation stands out markedly as furnishing the 

 largest amount of nitrogen. This is particularly due to the rains of 

 August, 1915, which not only were copious but very rich in all the 

 nitrogen compounds. 



The results for September and October indicate an exceptionally 

 high free ammonia content. This is due, as we have pointed out, to the 

 t-ain of these months in 1908 being seriously affected by smoke from 

 bush fires. 



Tables III and IV present the annual data for the composition 

 of the rain and snow, respectively, throughout the decade. 



Rain, it will be observed, is decidedly richer than snow in all the 

 nitrogen compounds. This is undoubtedly due to the greater solvent 

 action of the rain and not to any essential difference between the 

 concentration of the combined nitrogen of the air in summer and 

 in winter. In cases where both snow and rain fell on the same day 

 the rain invariably possessed a much higher nitrogen content. Further, 

 the winter rains show but little difference from those falling during 

 the warmer weather. The ratio of the total rainfall to that of snow 

 for the ten year period is 23-39 : 9-78, approximately 5 : 2 while the 

 ratio of the number of pounds of nitrogen per acre furnished by these 

 respectively is 5-4: 1-1, approximately 5:1, from which it will be 

 clear that rain is approximately twice as rich as snow. 



It will be noted that the percentage of nitrogen found as albumi- 

 noid ammonia is higher in snow (20%) than in rain (14%). The 



