76 
Experiments iipon Swedes. 
that we shall ever understand the action of complicated manures 
if we do not carefully study the separate effect of their component 
parts on vegetation. For this reason one plot was manured 
with sulpliate of ammonia, another with sulphate of lime 
(gypsum), a third with sulphate of potash, a fourth with chloride 
of sodium, and, finally, one with nitrate of soda. 
In the next place we have in Plot 17 phosphates chiefly in 
a soluble condition, and free from organic matter or anything 
else but sulphate of lime, which is necessarily produced when 
bone-ash is treated with sulphuric acid. In another plot (No. 18) 
we have the same materials in conjunction with sulphate of am- 
monia ; and in No. 20 we have them united with nitrate of soda. 
Then with respect to the form in which the nitrogen is applied in 
these experiments, I would observe that we find it in farmyard- 
manure, partly as ready-formed ammonia, partly in the shape of 
semi-decomposed nitrogenized organic matter. In sulphate of 
ammonia it exists, of course, as a salt of ammonia. In nitrate of 
soda we apply nitrogen in the shape of nitric acid. In guano 
nitrogen exists, partly only in the form of ammoniacal salts, the 
gi'eater portion of nitrogen being present as uric acid and other 
organic compounds which readily yield ammonia on decomposi- 
tion. And, lastly, we have in the turnip-manure all these dif- 
ferent forms in which nitrogen can be applied to the land 
combined together with phosphates. 
The results of these experiments, though unsatisfactory in 
some respects, are nevertheless intei'esting and suggestive in 
others, and worthy of some comments : — 
Plot 1. Manured with 15 tons of Farmyard-manure per Acre. 
tons. cwts. qrs. lbs. 
Produce 18 10 2 24 
Increase 3 IG 1 20 
Plot 2. Manured with 15 tons of Farmyard-manure and 2 cwts. of 
Superphosphate per Acre. 
tons. cwts. qrs. lbs. 
rroduce 17 6 3 4 
Iiicrease 2 12 2 0 
In comparing the weight of roots from these two plots, it 
would appear that the additional quantity of superphosphate has 
had rather an injurious than a beneficial effect. This, however, 
would be against common experience. It is probable that there 
were more plants on No. 1 than on No. 2. Let us suppose that 
there were 100 plants more on Pl^t'No. 1, and that each root on 
an average weighed 2 lbs. ; on calculating the increase per acre 
we should obtain nearly 1 ton more on the first plot than on 
the second, I legret not having counted the number of roots. 
