o the cheapest
sources of obtaining nitrogen, phosphoric acid, and potash. He has
certainly not overestimated their _cost_. They can not be bought at
lower rates, either in England or America. But of course it does not
follow from this that these manures are worth to the farmer the price
charged for them; that is a matter depending on many conditions. All
that can be said is, that if you are going to buy commercial manures,
you will have to pay at least as much for the nitrogen, phosphoric acid,
and potash, as the price fixed upon by Mr. Lawes. And you should
recollect that there are other ingredients in the manure obtained from
the food of animals, which are not estimated as of any value in the
table. For instance, there is a large amount of carbonaceous matter in
the manure of animals, which, for some crops, is not without value, but
which is not here taken into account.

Viewed from a farmer's stand-point, the table of money values must be
taken only in a comparative sense. It is not claimed that the manure
from a ton of wheat-straw is worth $2.68. This may, or may not, be the
case. But _if_ the manure from a ton of wheat-straw is worth $2.08,
_then_ the manure from a ton of pea-straw is worth $3.74, and the manure
from a ton of corn-meal is worth $6.65, and the manure from a ton of
clover-hay is worth $9.64, and the manure from a ton of wheat-bran is
worth $14.59. _If_ the manure from a ton of corn meal is _not_ worth
$6.65, then the manure from a ton of bran is not worth $14.59. If the
manure from the ton of corn is worth _more_ than $6.65, then the manure
from a ton of bran is worth _more_ than $14.59. There need be no doubt
on this point.

Settle in your own mind what the manure from a ton of any one of the
foods mentioned is worth on your farm, and you can easily calculate what
the manure is worth from all the others. If you say that the manure from
a ton of wheat-straw is worth $1.34, then the manure from a ton of
Indian corn is worth $3.33, and the manure from a ton of bran is worth
$7.30, and the manure from a ton of clover-hay is worth $4.82.

In this section, however, few good farmers are willing to sell straw,
though they can get from $8.00 to $10.00 per ton for it. They think it
must be consumed on the farm, or used for bedding, or their land will
run down. I do not say they are wrong, but I do say, that if a ton of
straw is worth $2.68 for manure alone, then a ton of clover-hay is worth
$9.64 for manu