42 
On the Rain and Drainage - Waters at Rothamsted. 
remembered in dealing with the figures given for the autumn 
period. The analyses made of autumn waters refer mostly to 
waters following dry summers, not that summer which fur- 
nished the analyses of summer waters. Although, therefore, it 
is quite true that the amount of nitrates rises in autumn in all 
cases where they have been much reduced in summer, the 
increase will not be so great in the case of many of the plots as 
would appear from the figures given for summer and autumn in 
the Table. In a side column of the Table is given the quantity 
of nitrogen in lbs. per acre removed on an average per inch of 
drainage-water. In the three years in question the average 
drainage shown by the 60-inch drain-gauge amounted to 17 "72 
inches per annum. 
The richness of the spring [waters (in wet seasons), where 
ammonium-salts or nitrate were applied ; the characteristic 
differences of the summer waters, depending on the action 
of the crop under different conditions as to the supplies of 
nitrogen and ash constituents ; the increase of nitric acid in 
autumn on plots where nitrates had been reduced in summer ; 
the generally similar character of the winter waters, the result of 
exhaustion by crop and drainage : and lastly, the considerable 
losses attending the autumn sowing of nitrogenous manures 
when followed by a wet winter, are the principal facts which 
will be found illustrated in the above Table. 
We have already seen (pp. 23, 34) that the composition of 
the waters from Plots 5-10 is not strictly comparable with that 
of the waters from Plots 11—15, the latter waters being, for some 
cause, imperfectly understood, somewhat more concentrated than 
the former. We may avoid this source of error if, instead of 
looking at the quantity of nitric acid in the different waters, we 
regard simply its relation to the chlorine ; this is shown in 
Table XLIX. 
Table XLIX. — Proportion of Xitrogex as Xiteic Acid to 100 of 
Chlorine in Dralsage-Waters from Broadbalk Field at different 
Seasons of the Year : average of Three Years. 
Plot. 
Ash coDstitaenis applied. { 
Spring. 
Sammer. 
Antumn. 
Winter. 
Whole 
Year. 
'{ 
Phos. Acid, Potash,! 
Magnesia, Soda ../ 
311 
6-9 
20-2 
45 1 
29-4 
17 or 18 
Ditto ditto .. .. 
30-3 
69 
181 
43-9 
27-8 
13 
Phos. Acid, Potash .. 
311 
6-3 
14-4 
44-2 
261 
14 
„ „ Magnesia 
32-1 
10-8 
17-3 
53-4 
30-7 
12 
„ ,, Soda 
33-2 
121 
180 
511 
30-6 
11 
Phosphate alone .. 
43-8 
18-3 
19-5 
51-2 
34-4 
10 
43-6 
38-7 
37G 
531 
440 
