Various rnosriiATlc manures on urlanij soil. 
ii 
Phosp bo¬ 
ric acid 
originally 
applied. 
grms. 
Kind of 
Phosphate. 
Dry 
matter 
produced. 
grins. 
Plus-yield over the 
plots without 
phosphoric acid. 
Plus-yield 
by 100 
grms. of 
phosphoric 
acid. 
ist and 2nd 
crops. 
grms. 
Grms. 
Caused 
by 100 
grms. of 
phospho¬ 
ric acid, 
gnns. 
O 
No phospbatic manure ... 
479 
— 
_ 
— 
1413 
Double superphosphate ... 
144. i 
96.2 
6S01 
20729 
2.826 
it 
it ... 
164.1 
116.2 
4112 
15184 
1.696 
Steamed bone dust. 
143-5 
95-6 
5637 
^793 
3-392 
it 
tt it . 
179 2 
I 3 1 3 
3871 
12138 
2.120 
Precipitated calcium plios. 
162.7 
114.8 
5415 
13802 
4.240 
ft tt tt 
1717 
123.8 
2920 
9387 
1.696 
Crude bone dust . 
154.8 
106.7 
6291 
138S5 
3392 
tt 
tt tt . 
258.1 
210.2 
6197 
13438 
1.696 
Raw crushed bones. 
128.1 
80.2 
4729 
12200 
3392 
it 
tt tt . 
I64.2 
116.3 
3429 
10553 
2 120 
Thomas phosphate. 
88 7 
40.8 
1925 
8675 
4.240 
tt . 
1387 
90 8 
2193 
8073 
2.826 
Bone ash. 
107.3 
59-4 
2102 
4837 
5-652 
ft 
it . 
150.8 
102.9 
1S21 
5075 
There was, accordingly, in all cases a considerable action of the 
unrecovered phosphoric acid, which, in some cases (crude bone 
dust and precipitated calcium phosphate) was as high, or nearly as 
high, as after the fresh application of the manure to the first crop. 
The best after-effect was displayed by the double superphosphate; 
then followed the crude bone dust, steamed bone dust, precipitated 
phosphate, raw crushed bones, Thomas phosphate, and finally the 
bone ash. A calculation also based on the plus-yield produced 
by ioo grams of phosphoric acid applied in the smaller doses, 
gives the following figures for the action of the various phosphates 
on the first two crops (winter barley and-millet) : 
