ON MANURING FOR HOPS. 205 



Saltpetre contains aljout 47 per cent, of potash, and pearl- 

 ash about 68 per cent. By calculation, therefore, we find 

 that 64 lb. of potash taken from the land by a crop of hops 

 would be rejilaced by 130 lb. of saltpetre, at a cost of about 

 S2s., or by 94 lb. of pearlash, at a cost of about 3'3s. 



The weights of saltpetre or pearlash given above would 

 supply the deficiency of potash, supposing- the whole crop, 

 including bine, leaves, and hops, were removed from the 

 land. But if the bine and leaves be allowed to rot on the 

 gTound, about one-sixth less than the preceding amounts 

 Avouldbe sufficient. The impropriety, therefore, of removing 

 the bine, <fcc., from the land, as is too often the case, is very 

 apparent. 



One of the most important points to be deduced from 

 these analyses is the ])reparation, at a reasonable expense, 

 of a manure which shall contain all the necessary mineral 

 ingredients for the growth of the hop. Being- engaged in 

 the analyses of various other sam})les of the hop, I am now 

 unwilling to oft'er, as perfect, any manure for the ho]), i;ntil 

 the comparison of diH^erent varieties shall have shown that 

 the hops in divers localities agree in the per-centage of their 

 various constituents. 



It will be seen by reference to the analyses, that, besides 

 potash, the hops contain phosphoric acid, lime, magnesia, 

 common salt, and silica. About 3 cwt. of guano wordd 

 supply the necessary amount of ])hosphates. The chloride 

 of sodium would be amply sup})lied by 1 cwt. of common 

 salt. Lime and magnesia are doubtless found in sufficient 

 quantities in the land ; or if not, they can easily be sup- 

 plied. The silica, perhaps, may be found in sufficient quan- 

 tities in the land, though it might be better to supply both 

 silica and potash together, in the shape of silicate of })otash. 

 This compound, however, is not at ])resent an article of com- 

 merce, but there is a probability that it will soon be manu- 

 factured on a large scale. The sidjihuric acid can be sup- 

 plied by gypsum. 



Either of the following mixtiu-es might be worth trial for 

 promoting the growth of the hop : — 



Maniirefor an Acre of ITops.] 



s. d. £ s. d. 



3 cwt. guano, at 8 per cwt 1 4 



1 cwt. common salt, at ....1 0,, ,, ....0 1 

 I5 cwt. saltpetre, or Ij cwt. 



silicate of potash, at 2G G ,, ,, 1 10 9 



J cwt. gypsum 1 6 ,, ,, .... 9 



Cost per acre ^3 5 G 



