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ANALYSIS OF SOILS. 
The analyses were conducted through two operations. The first was precisely that by 
which we obtained the results already stated. The silicates, alumina and iron, lime and 
magnesia, were severally obtained by the usual methods. To secure exactness, the double 
filters were always well washed, dried, burnt and weighed. We then tested for phosphates, 
by redissolving the alumina and iron in chlorohydric acid : the soluble silex was separated 
by filters, and, if in a decidedly appreciable quantity, it was weighed. The solution being 
freed from silica, was exactly neutralized by caustic ammonia, and the phosphates, if any 
existed, were thrown down by a solution of acetate of potash. Sometimes the phosphate 
of alumina and phosphate of the peroxide of iron did not immediately appear, but, in the 
course of five or six hours, it would become perceptible, and in twenty-four hours it 
subsided. In some cases its presence would be sensible, but its quantity so small that it 
did not appear of sufficient importance to filter and weigh. The iron and alumina were 
not separated. 
Having subjected the alumina and iron to the above test for phosphates, we then took 
up the farther examination of the silicates obtained in the first operation. This was, in 
the first place, fused in a platina crucible, with three times its weight of carbonate of soda. 
The fused mass was then dissolved out by boiling water acidulated with hydrochloric acid, 
evaporated to dryness, and then redissolved ; when it was subjected to the same course of 
treatment, for alumina, iron, lime, magnesia, potash and soda. 
By this treatment, we supposed the capability of the soil would be determined. The 
advantages of this double process consist in obtaining first the elements which are more 
immediately available to the crops ; and, in the second process, we learn the amount of 
the elements which are more securely locked up by the silica for future use. Both ope¬ 
rations give the capabilities of the soil. In the second operation, phosphates are never 
obtained, but lime, alumina, iron and some magnesia usually ; and in a few instances, 
where the soil contained much matter from the primary rocks, a greater amount of lime 
was obtained than by the first operation : the amount of magnesia is much less also. The 
phosphates of the soil which have been derived in the last place from animal or vegetable 
origin, may be expected to be easily dissolved ; and it is quite doubtful whether any exists 
in any soil, which may not be dissolved and obtained by the first operation. They pro¬ 
bably exist in fine particles in the soil as phosphate of lime and alumina, and, if so, are 
almost as soluble as the phosphates contained in bones. The phosphates, then, so far 
as they exist, are always soluble, and never locked up in combination with an acid, such 
as will not yield to the action of the weak organic acids, which are formed in the soils by 
peculiar changes that take place in woody fibre and other vegetable products. 
The process by which soluble silica was obtained, we deem highly important. We 
believe we do not err when we state that silica is an element equally important in vegeta¬ 
tion with the phosphates, or the potash and alkaline earths. It is a mistaken notion, if it 
exists, that fertility is due to any one element; that a good crop of corn can be raised, 
provided the phosphates, or any other one of the necessary elements, are in sufficient 
