300 
MESSRS. J. B. LA WES AND J. H. GILBERT ON THE RESULTS OF 
relating to the effects of different manures upon it will be the more easily under¬ 
stood. 
The next point to be considered is the effects of certain characteristically different 
conditions as to manuring, each, respectively, continued for many years in succession on 
the same plot. 
1. Without Manure ; Plots 3 and 12. 
Tiie following table shows the average produce of hay obtained, per acre per annum, 
without any manure, over the first 10 years, the second 10 years, and the total period 
of 20 years, from 1856 to 1875 inclusive; also the amounts of nitrogen, and min eral 
matter (ash), which the hay contained. 
Table II. —Average, per acre per annum, without Manure. 
Arerage per acre per annum. 
Plot 3. 
Plot 12. 
Mean. 
Hat. 
lbs. 
lbs. 
lbs. 
First period, 10 years, 1856-1865 . 
2531 
2808 
2670 
Second period, 10 years, 1866-1875 . 
2236 
2564 
2400 
Total period, 20 years, 1856-1875 . 
2383 
2686 
2535 
Second period, per cent. + or — first period 
-117 
-8-7 
-lOT 
Nitrogen. 
First period, 10 yeai’s, 1856-1865 . 
35 T 
39-3 
37-2 
Second period, 10 years, 1866-1875 . 
30-9 
35-6 
33-3 
Total period, 20 years, 1856-1875 . 
33-0 
37 - 5 
35-3 
Second period, per cent. + or — first period 
-12-0 
— 9-4 
-10-5 
Mineral Matter (Ash). 
First period, 10 years, 1856-1865 . 
148-5 
161-7 
155-1 
Second period, 10 years, 1866-1875 . 
126-1 
143-2 
134-6 
Total period, 20 years, 1856-1875 . 
137-3 
152-4 
144-9 
Second period, per cent. + or — first period 
-15-1 
-11-4 
-13-2 
It will be seen that, over both periods, one of the unmanured plots (12) yielded 
more produce of hay than the other (3). It also yielded more nitrogen, and more 
mineral matter, whilst, in all three particulars—hay, nitrogen, and mineral matter—- 
its decline in yield over the second period compared with the first was less. For a 
long time the proper explanation of this superiority was not very obvious ; but it was 
