254 On the Rain and Drainage -Waters at Rothamsted. 
Table VIII. — Nitrogen as Ammonia in Monthly Rainfalls arranged 
according to the Amount of Fall. 
A vprape 
Rainfall. 
Nitroi;en 
as Ammonia, 
per Million. 
inches. 
0-624 
1-06 
Rainfall between 1 and 2 inches (9 montlis) .. 
1-530 
1-17 
Rainfall between 2 and 3 inches (16 months) .. 
2-473 
0-91 
4-727 
0-82 
The smallest rainfall does not here contain the largest propor- 
tion of ammonia, the maximum of ammonia occurring in the rain- 
fall standing second in the Table, but on the whole the proportion 
of the ammonia plainly falls as the amount of rain increases. 
The nitrogen existing as nitric acid follows a similar order. 
The rain of three months in which the fall was below one inch, 
contained as an average 0'12 of nitrogen as nitric acid per 
million. The average of eight months, with a fall between one 
and two inches, was 0*14 of nitrogen per million. Ten months, 
with a fall between two and three inches, gave an average of 
0-12 of nitrogen per million; while three months, with a fall 
exceeding three inches, gave O'lO of nitrogen per million. 
It appears that the smallest rainfall was not quite the richest 
either in ammonia or nitric acid. It may of course happen that 
a small monthly rainfall may not be a distributed one, but fall 
in a few heavy showers, A more general explanation appears 
to be that the conditions most favourable to a high proportion 
of ammonia in the rain-water (as a sudden change from a warm 
to a cold wind) are conditions generally attended by a somewhat 
considerable rainfall. 
The determinations of ammonia made in three years' rainfall, 
and the determinations of nitric acid in two years' rainfall, lead 
to the following conclusions as to the quantity of nitrogen in 
these forms annually supplied to the soil by rain. 
Table IX. — Nitrogen as Ammonia and Nitric Acid in the Rainfall 
of Three Years, in lbs. per Acre. 
Years. 
Rainfall. 
Nitrogen per Acre, as 
Ammonia. 
Nitric Acid. 
Total Nitrogen. 
1853-1 
1855 
1856 
inches. 
29-014 
29-166 
27-215 
lb.s. 
5-20 
5-82 
7 28 
lbs. 
[0-74] 
0-72 
0-76 
lbs. 
5- 94 
6- 58* 
8-00* 
Mean . . 
28-465 
6-10 
0-74 
6-84 
* These figures stand respectively as 6 -63 lbs., and 8-31 lbs. in Way's original 
])nper; the figures in this Table are more co-reft. 
