Home Manufacture of Portable Manures. 
273 
the percentage of soluble phosphates. If required for application 
shortly after preparation, care must be taken that calcareous 
matters (chalk or lime) are not used as drying materials, which 
would to a certain extent neutralise the acid, and consequently 
reduce the solubility of the phosphates. Dry bone-ash or bone- 
meal will suit the purpose well. Having thus arrived at the 
basis from which most of the best manures are made, what remains 
to form a compound manure is a very simple affair, because, as far 
as the farmer is concerned, according to the quantity of am- 
monia added, a manure will be formed rich or poor as the maker 
may choose. To derive the full effect from phosphoric acid, it 
must be conjoined with ammonia. Now, for agricultural purposes 
genuine Peruvian guano is the cheapest source of ammonia ; 
therefore a mixture of pure bone superphosphate and Peruvian 
guano (proportioned according to the crop and soil for which it 
is intended), will form a phospho-Peruvian guano or manure 
(call it what you like) of money value equal to any manure sold^ 
and infinitely superior to the greater portion of compound manures- 
in the market. The mixture improves the power of each, the 
free acid of the superphosphate fixing the ammonia in the guano,, 
which is besides presumed by some chemists to exert an influence 
in decomposing mineral ingredients in the soil. Should at 
any time a difficulty occur in procuring a supply of suitable 
materials for making superphosphate, then purchase genuine 
South American or other good phosphatic guano, of which take 
3 tons and mix with 1 ton of Peruvian guano, and the result in 
ordinary cases, when applied to root-crops, will equal 4 tons of 
Peruvian per se. The proportions can be varied according to- 
circumstances. Peruvian guano alone in a very dry season like 
1859, proved in many places nearly a failure in comparison with 
this mixture, and inferior in promoting the growth of turnips to- 
South American guano unmixed, as will be seen from the annexed 
published report of experiments made in 1859 on the growth 
of turnips- with different manures by the Inverness Farmers' 
Society (see p. 274). 
Among these nineteen carefully-selected manures, it was proved 
that the same money value of South American guano produced 
about 4 tons more turnips per acre than Peruvian guano, and 
much more in proportion than any of the other manures named 
and detailed in the above report — the Peruvian guano producing 
per imperial acre 13 tons 2 cwt. 17 lbs., at a cost of 3*. 9J(i. 
per ton, and the South American guano 17 tons 2 cwt. 3 qrs. 
7 lbs., at a cost of 35. 2\d. per ton. The cost of the manures I 
have recommended will not exceed 8Z. per ton, taking the price 
of pure dissolved bones and South American guano at 6Z. 5^. and 
6^. 10s. per ton, and Peruvian guano at 12/. \0s. per ton ; and 
VOL. XXIII, T they 
