Artificial Manures for Swedes. 
99 
behind by the superphosphate, and probably also by the dis- 
solved coprolites, mixed with guano ; and the result has proved 
that this was actually the case. The guano was best Peruvian, 
and was bought at the price of 10/. per ton. On analysis its 
composition was ascertained to be as follows : — 
Water 12-420 
Orfjanic matter and ammoniacal salts 62 '980 
Phosphates of lime and magnesia (bone-earth) 25-065 
Alkaline salts, chiefly chloride of potassium and sodium, 
w ith a small quantity of alkaline phosphates and sul- 
phates 8-262 
Insoluble siliceous matter 1-507 
100-234 
Containing nitrogen 14-177 
equal to 
Ammonia 17-215 
The guano employed in the experimental trial, as shown by- 
its analysis, was genuine Peruvian guano of good qualities. 
Inferior kinds of guano, such as Saldanha-bay and Patagonian, 
I think, would have given a better result, for they are richer in 
phosphates than Peruvian ; and as the commercial value of 
guano is principally regulated by the proportion of ammonia it 
contains or furnishes on decomposition, and as ammonia does 
not benefit root crops in an equal degree as white crops, whereas 
phosphatic manures exercise a specific action on roots, which 
causes them to swell and thus to increase the crop, it would 
appear that, to the extent to which Peruvian guano is richer in 
nitrogenized matters than other kinds of guano, it becomes less 
valuable. Indeed, it appears to me a great waste to apply 
Peruvian guano alone to swedes or turnips ; and I hope to sup- 
port this opinion by the practical proofs which will presently 
be mentioned. 
Plot II. Manured with 84 lbs. of coprolites dissolved in sulphuric acid 
and 28 lbs. of guano, or at the rate of 6 cwts. dissolved copro- 
lites and 2 cwts. of guano. 
Cost of manure 5s., or 21. per acre. 
At first no difference in the appearance of the swedes, when 
compared with those grown with guano alone, could be observed ; 
but at a more advanced season the roots looked decidedly better 
than those of Plot I., and, indeed, of most other experimental 
plots. 
The dissolved coprolites were made on the farm by digesting 
the finely ground, so-called Suffolk coprolites, with one-third 
their weight of sulphuric acid, and allowing this mixture to 
become nearly air-dry by keeping. It was then mixed with 
guano, and thereby obtained in a perfectly powdered and air- 
dry state. 
H 2 
