On the Composition of Waters of Land-Draincujc. 139 



Table sJwicing the amount of Ammonia and Nitric Acid in Rain-Water, 

 1855, in Grains per Imperial Gallon {Professor Way). 



Ammonia. Nitric Acid. 



January "092 .. .. -017 



February -104 .. .. -042 



March -086 .. .. -021 



April -123 .. .. -035 ■ 



May .. -080 .. .. -035 



June -135 .. .. -080 



July -061 .. .. -017 



August -080 .. ., -060 



September '095 .... -021 



October.. .. -061 .. .. -036 



November -054 .... -018 



December -067 .... -017 



The mean quantity for the whole year is 0'86 grains in a 

 gallon, or about 1'228 parts in a million of water according to 

 Professor Way ; and Mr. Lawes and Dr. Gilbert found, in their 

 experiments in 1853 and 1854, on an average, as nearly as 

 possible 1 part of ammonia in a million of rain. 

 f ^On comparing the amount of ammonia in rain-water with the 

 proportions which I found in the preceding drainage-waters it 

 will be seen that the latter, without exception, contain less 

 ammonia than rain. It follows from these observations that the 

 ammonia in rain, as well as that contained in ammoniacal 

 manures, and that produced during the decomposition of nitro- 

 genous fertilising matters, is either absorbed by the soil, or that 

 it is probably oxydised and converted into nitric acid. I may 

 state here at once that I have examined drainage-water collected 

 at all times of the year, and never found more than mere traces 

 of ammonia in them, whereas the proportion of nitric acid in 

 Avaters from land-drainage is nearly always more considerable 

 than in rain-water, and, at times, very large indeed. 



10. This leads to the consideration of the remarkable occur- 

 rence of nitric acid, or, more correctly speaking, nitrates in the 

 drainage-water from land upon which nitrates have never been 

 applied. 



From the preceding calculated results it will be seen that the 

 drainage from all the plots contained more or less nitric acid, 

 and that even that from the plot upon which no manure what- 

 ever had been used for 25 years, contained an appreciable amount 

 of nitric acid. 



It is interesting to notice that the continuously unmanured 

 Plots 3 and 5 furnished drainage-water poorer in nitric acid than 

 any of the other plots, and that the influence of the application 

 of ammoniacal salts to Plot 16 before 1865 is still perceptible in 

 the slightly larger proportion of nitric acid which was found in 

 the drainage of Plot 16. 



