nts. No one would think of using sulphate of
ammonia at its price, [sulphate of ammonia is now cheaper, while
Peruvian guano is more costly and less rich in ammonia], as an ordinary
manure, for the reason, that the same quantity of ammonia can be
obtained in other substances, such as barnyard-manure, Peruvian guano,
etc., at a much cheaper rate. But these manures contain _all_ the
elements of plants, and we can not know whether the effect produced by
them is due to the ammonia, phosphates, or any other ingredients. For
the purpose of experiment, therefore, we must use a manure that
furnishes ammonia without any admixture of phosphates, potash, soda,
lime, magnesia, etc., even though it cost much more than we could obtain
the same amount of ammonia in other manures. I make these remarks in
order to correct a very common opinion, that if experiments do not
_pay_, they are useless. The ultimate object, indeed, is to ascertain
the most profitable method of manuring; but the _means_ of obtaining
this information, can not in all cases be profitable.

"Similar experiments to those made on Indian corn, were made on soil of
a similar character, on about an acre of Chinese sugar-cane. I do not
propose to give the results in detail, at this time, and allude to them
merely to mention one very important fact, _the superphosphate of lime
had a very marked effect_. This manure was applied in the hill on one
plot (the twentieth of an acre,) at the rate of 400 lbs. per acre, and
the plants on this plot came up first, and outgrew all the others from
the start, and ultimately attained the height of about ten feet; while
on the plot receiving no manure, the plants were not five feet high.
This is a result entirely different from what I should have expected. It
has been supposed, from the fact that superphosphate of lime had no
effect on wheat, that it would probably have little effect on corn, or
on the sugar-cane, or other _ceralia_; and that, as ammonia is so
beneficial for wheat, it would probably be beneficial for corn and
sugar-cane. The above experiments indicate that such is the case, in
regard to Indian corn, so far as the production of grain is concerned,
though, as we have stated, it is not true in reference to the early
growth of the plants. The superphosphate of lime on Indian corn,
stimulated the growth of the plants, in a very decided manner at first,
so much so, that we were led to suppose, for some time, that it would
give