cid_ to the soil.

Liebig says that, as a producer of ammonia, 100 lbs. of dry bones are
equivalent to 250 lbs. of human urine.

[How does the value of bone dust compare with that of broken
bones?

What is the reason of the superiority of bone dust?

How is bone-black made?

Of what does it consist?]

Bones are applied to the soil in almost every conceivable form. _Whole
bones_ are often used in very large quantities; their action, however,
is extremely slow, and it is never advisable to use bones in this form.

Ten bushels of bones, finely ground, will produce larger results, during
the current ten years after application, than would ensue from the use
of one hundred bushels merely broken, not because the dust contains more
fertilizing matter than the whole bones, but because that which it does
contain is in a much more available condition. It ferments readily, and
produces ammonia, while the ashy parts are exposed to the action of
roots.

[Should farmers burn bones before using them?

How would you compost bones with ashes?

In what way would you prevent the escape of ammonia?]

_Bone-black._ If bones are burned in retorts, or otherwise protected
from the atmosphere, their organic matter will all be driven off, except
the carbon, which not being supplied with oxygen cannot escape. In this
form bones are called _ivory black_, or _bone-black_. It consists of the
inorganic matter, and the carbon of the bones. The nitrogen having been
expelled it can make no ammonia, and thus far the original value of
bones is reduced by burning; that is, one ton of bones contains more
fertilizing matter before, than after burning; but one ton of bone black
is more valuable than one ton of raw bones, as the carbon is retained in
a good form to act as an absorbent in the soil, while the whole may be
crushed or ground much more easily than before being burned. This means
of pulverizing bones is adopted by manufacturers, who replace the
ammonia in the form of guano, or otherwise; but it is not to be
recommended for the use of farmers, who should not lose the ammonia,
forming a part of bones, more than that of other manure.

_Composting bones with ashes_ is a good means of securing their
decomposition. They should be placed in a water-tight vessel (such as a
cask); first, three or four inches of bones, then the same quantity of
strong unleached wood ashes, continuing these alternate layers until the
cask is full, and keeping th