til the spring.

The formation of nitric acid, from the organic nitrogen in the soil, is
due to the action of a minute plant, and goes on quite independent of
the growth of our crops. We get, however, in the fact an explanation of
the extremely different results obtained by the use of different
manures. One farmer applies lime, or even ground limestone to a soil,
and obtains an increase in his crops; probably he has supplied the very
substance which has enabled the nitrification of the organic nitrogen to
increase; another applies potash, a third phosphates; if either of these
are absent, the crops cannot make use of the nitric acid, however great
may be the amount diffused through the soil.

It may possibly be said that the use of mineral manures tends to exhaust
the soil of its nitrogen; this may, or may not, be true; but even if the
minerals enable the crop to take up a larger amount of the nitric acid
found in the soil year by year, this does not increase the exhaustion,
as the minerals only tend to arrest that which otherwise might be washed
away.

We must look upon the organic nitrogen in the soil, as the main source
of the nitrogen which grows our crops. Whatever may be the amount
derived from the atmosphere, whether in rain, or dew; or from
condensation by the soil, or plants, it is probable that, where the land
is in arable cultivation, the nitrogen so obtained, is less than the
amount washed out of the soil in nitric acid. Upon land which is never
stirred by the plow, there is much less waste and much less activity.

The large increase in the area of land laid down to permanent pasture in
England, is not due alone to the fall in the price of grain. The
reduction of fertility in many of the soils, which have been long under
the plow, is beginning to be apparent. Under these circumstances a less
exhausting course of treatment becomes necessary, and pasture, with the
production of meat, milk, and butter, takes the place of grain fields.

APPENDIX.

Letter from Edward Jessop, York, Pa.

YORK, PA., March 16, 1876.

_Joseph Harris, Esq., Moreton Farm, Rochester, N.Y.:_

DEAR SIR--Your favor of the 22d of last month came safely to hand, and I
am truly obliged to you for the reply to my question.--You ask, can I
help you with facts or suggestions, on the subject of manure? I fear not
much; but it may be useful to you to know what others need to know.
I will look forward to the advent of "Talks on