12 Artificial Manures for Swedes. 



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 



Organic matter and ammoniacal salts 52 980 



Phosphates of lime and magnesia (bone-earth) 25-065 



Alkaline salts, chiefly chloride of potassium and sodium, 

 with 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, 

 1 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 Ibs. of coprolites dissolved in sulphuric acid 

 and 28 Ibs. of guano, or at the rate of 6 cwts. dissolved copro- 

 lites and 2 cwts. of guano. 

 Cost of manure 5., or 21. per acre. 



At first no difference in the appearance of the swedes, when 

 compared witli 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. 



