«4 
Comparative experiments on the effect of 
Kind of Phosphate. 
Phospho¬ 
ric acid 
originally 
applied. 
grms. 
Dry 
! matter 
! produced. 
grms. 
Increase of the yield 
over the plots without 
phosphoric acid. 
Increase 
by 100 
grms. 
phosphoric 
acid, 
ist, 2nd, 
and 
Trd crop, 
grms. 
Grms. 
Caused 
by 100 
grms. 
phospho¬ 
ric acid, 
grms. 
No pbosphatic manure ... 
O 
39-6 
— 
— 
— 
Double superphosphate ... 
1413 
95 -° 
55-4 
3921 
24650 
it ft 
2.826 
166.1 
126.5 
4476 
19660 
Steamed hone dust*. 
1.696 
( 71 - 7 ) 
— 
— 
(20805) 
it it it . 
3-392 
775-7 
136.1 
4012 
16150 
Precipitated calcium phos. 
2.120 
123-3 
« 3-7 
3950 
17752 
5 » it ft 
4.240 
193 - 1 
153-5 
3620 
13007 
Crude bone dust . 
1.696 
221.5 
181.9 
10725 
24610 
it ft ft . 
3-392 
3 M -9 
275-3 
8116 
21554 
Raw crushed bones. 
1.696 
255-3 
215-7 
12718 
24918 
tt tt tt . 
3-392 
338-9 
299-3 
8824 
19377 
Thomas phosphate. 
2.120 
77-9 
38-3 
1807 
10482 
tt tt . 
4.24O 
III.O 
71.4 
1684 
9757 
Bone ash . 
2.826 
144-1 
1045 
3698 
8535 
it t> . 
s - 6 52 
201.5 
161.9 
2864 
7939 
Calculating now the relative increase of dry matter produced 
by equal quantities of the various forms of phosphoric acid, 
assuming the effect of the superphosphate to be ioo, we find the 
following results : 
Relative increase 
of dry matter, 
ist, 2nd, & 3rd crops. 
Double superphosphate . 
*.IOO 
Steamed bone dust . 
. 84.4 
.Precipitated calcium phosphate . 
. 72.0 
Crude bone dust. 
. 99-9 
Raw crushed bones . 
.IOI.I 
Thomas phosphate . 
. 42.5 
Bone ash . 
. 34-6 
* As the plots with the smaller dose of steamed bone dust had been injured by frost, we 
calculated in the above table the increase caused by 100 grams phosphoric acid of ibis 
dose from the yield obtained with the larger quantity of that fertilizer. 
