already in a pulverulent state,
while bones have to be reduced by mechanical or chemical means to the
same condition before they are of any use as manure. Do not, we again
repeat most emphatically, do not waste a bone; dissolve all you can get
in sulphuric acid and mix with guano--save and make all the manure
possible, both by the stable, compost heap and green crops, and then you
will have money to buy guano, by which you can save the immense labor of
hauling to distant fields, and still have the satisfaction of seeing
them as fertile as those highly manured near home.

When the farmer raises crops for sale, and removes his grain and grasses
from the land, he sells a portion of his soil; and if he does not renew
in some way the saline matters taken away in his crops, he invariably
impoverishes his farm. This work of exhaustion is now going on to an
alarming extent, and the prolific wheat lands are to be searched for
farther and farther westward as the operation proceeds.

Every one knows the superiority of wheat grown on newly cultivated
lands, and most farmers are aware of the fact that soils become
exhausted of something, they know not what, but of something essential
to the most favorable production of grain. This something is found in
guano, and by it the original fertility of land can be more easily, more
certainly and cheaply restored than by any other means as yet
discovered.

Professor Mapes in one of his letters of advice says; "As no farm, under
ordinary usage, will supply as much manure as may be used upon it with
profit, I am glad you intend to use guano, as it is an admirable manure,
replete with many requirements of plants. The ammonia of the guano is in
the form of a carbonate, and therefore so volatile as to escape from the
soil into the atmosphere before plants can use it.

"You will readily perceive, therefore, that the sulphuric and phosphoric
acids require amendments, and the ammonia should be changed from a
carbonate to a sulphate of ammonia, which is not volatile. All this may
be readily done by dissolving bone dust in dilute sulphuric acid, mixing
it with the guano, and then with a sufficient amount of charcoal dust to
render the mass dry and pulverulent. The more charcoal dust the better,
as it absorbs and retains ammonia, and after it is in the soil, will
continue to perform similar offices for many years, only yielding up
ammonia as required by plants, and receiving new portions from rains,