328 MESSRS. J. B. LAWES AND J. H. GILBERT ON THE RESULTS OF 
addition to the ammonia-salts and the usual mixed mineral manure, artificial silicates 
were thenceforward applied ; for nine years (1862-1870), 200 lbs. of a crude silicate of 
lime, and 200 lbs. of a crude silicate of soda, and afterwards 400 lbs. of the silicate of 
soda, per acre per annum, were employed. 
The following table shows the produce of hay, of nitrogen, and of mineral matter, 
over the first 10, the second 10, and the total period of 20 years, on each of the two 
portions of the plot—11-1 continuously without, and 11-2 for the last 14 years with, 
the silicate. For comparison there is also again given, the results obtained on plot 9, 
with the same mixed mineral manure and only 400 lbs. of ammonia-salts, per acre per 
annum, over the whole period. 
Table XI.—Average, per acre per annum, by 800 lbs. (or 400 lbs.) of Ammonia- 
Salts, and Mixed Mineral Manure, without, and with, the addition of Silicates ; Plots 
11-1 and 11-2. 
Average per acre per annum. 
Plot 9. 
Mineral manure, 
and 400 lbs. 
ammonia-salts. 
Plot 11-1. 
Mineral manure, 
and 800 lbs.* 
ammonia-salts. 
Plot 11-2. 
As plot 11-1, 
and silicates. 
Plot 11-1. 
+ or — 
plot 9. 
Plot 11-2. 
+ or — 
plot 11-1. 
Hat. 
lbs. 
lbs. 
lbs. 
lbs. 
lbs. 
First period, 10 years, 1856-1805 .... 
6002 
6913 
7077 
+ 911 
+ 164 
Second period, 10 years, 1866-1875 . . . 
5421 
6006 
6909 
+ 585 
+ 903 
Total period, 20 years, 1856-1875. . . . 
5711 
6459 
6993 
+ 748 
+ 534 
Second period, per cent. + or — first period 
-9-7 
-13-1 
-2-4 
N ITEOGEN. 
First period, 10 years, 1856-1865 .... 
75-7 
102-7 
103 7 
+ 27-0 
+ 1-0 
Second period, 10 years, 1866-1875 . . . 
70-7 
103-5 
111-7 
+ 32-8 
+ 8-2 
Total period, 20 years, 1856-1875 .... 
73-2 
1031 
107-7 
+ 29-9 
+ 4-6 
Second period, per cent. + or - first period 
-6-6 
+ 0-8 
+ 7-7 
Minekal Matter (Ash). 
First period, 10 years, 1856-1865 .... 
368-3 
420-7 
435-9 
+ 52-4 
+ 15-2 
Second period, 10 years, 1866-1875 . . . 
301-0 
339-7 
392-1 
+ 38-7 
+ 52-4 
Total period, 20 years, 1856-1875 . . . . 
334-6 
380-2 
414-0 
+ 45-6 
+ 33-8 
Second period, per cent. + or — first period 
-18-3 
-19-3 
-10-1 
Thus, an increased supply of ammonia-salts, with the same mineral manures as on 
plot 9, has considerably increased the annual produce of hay, but in a much greater 
* 400 lbs. only in 1859, i860, and 1801. 
