On the Rain and Drainage - Waters at Rothainsted. 17 
It will be seen that while the total solid matter, and especially 
the nitrates and chlorides, are greatly diminished in the turbid 
water, the organic matter and the ammonia have greatly in- 
creased. The excess of organic matter in turbid waters, and 
the increase in the proportion of carbon as the turbidity 
increases, have been already noticed when speaking of the 
waters from the drain-gauges ; the same facts reappear in the 
analyses of the Broadbalk waters, as will be seen by a glance at 
the following numbers representing, in parts per million, the mean 
results found by Dr. Frankland for the waters from Plots 2-15. 
Condition of Waters. 
Xnmber of 
Analynes. 
Organic 
Carbon. 
Organic 
Nitrogen. 
Ratio of Xitrogen 
to Carbon. 
Clear 
20 
1-31 
0-44 
1 : 3-03 
32 
1-87 
0-47 
1 : 401 
Turbid 
28 
2-46 
0-59 
1 : 415 
G 
7-55 
1-69 
1 : 4-48 
The proportion of carbon to nitrogen in the drainage-waters 
from cropped land is seen to be rather higher than in the waters 
from a bare fallow (see Part II. vol. xvii. p. 336). 
As an illustration of the different composition of drainage- 
waters at the commencement and end of a running, we give on 
the next page the amounts of nitric acid and chlorine found in 
the drainage-waters collected on the evening of June 2, 1879, 
and on the morning of the following day. The evening col- 
lection was made about one hour after the drains had started 
running ; the collection next morning was made when the 
drains were ceasing to run. 
The increase in the chlorides and nitrates towards the end of 
the running is here extremely striking. The waters collected 
on June 2 were all more or less turbid, especially those from 
Plots 3&4, 5, 9, and 12-18. The waters caught on June 3 were 
all clear. This year the ammonium-salts were applied to Plot 15 
in autumn, and to all other plots in the spring. 
We have already stated that the rule that drainage-waters 
increase in strength towards the end of the running is true in all 
cases in which the soluble salts are at the time tolerably diffused 
throughout the soil ; it applies, in fact, to those cases only. 
VVhen soluble manures have recently been applied to the surface, 
the drainage-waters always decrease in richness towards the end 
of the running. In this case the layer of soil richest in soluble 
salts is considerably above the level of the drains. As after rain 
has ceased, the upper layer of soil will be the first to cease 
VOL. XVIII. — S. S. 0 
