lebrook, Conn., that it "has
been used to some extent as a top-dressing for grass and other crops
with satisfactory results, _although no particular benefit was
noticeable during the first year_. After that, the effects might be seen
for a number of years."

Rev. Wm. Clift observes, concerning a salt peat, from Stonington,
Conn.:--"It has not been used fresh; is too acid; even potatoes do not
yield well _in it the first season_, without manure."

The nature of the chemical changes induced by weathering, is to some
extent understood so far as the nitrogen, the most important fertilizing
element, is concerned. The nitrogen of peat, as we have seen, is mostly
inert, a small portion of it only, existing in a soluble or available
form. By weathering, portions of this nitrogen become converted into
nitric acid. This action goes on at the surface of the heap, where it is
most fully exposed to the air. Below, where the peat is more moist,
ammonia is formed, perhaps simply by the reduction of nitric acid--not
unlikely also, by the transformation of inert nitrogen. On referring to
the analyses given on page 44, it is seen, that the first two samples
contain but little ammonia and no nitric acid. Though it is not stated
what was the condition of these peats, it is probable they had not been
weathered. The other four samples were weathered, and the weathering had
been the more effectual from the large admixture of sand with them. They
yielded to the analyst very considerable quantities of ammonia and
nitrates.

When a peat contains sulphate of protoxide of iron, or soluble organic
salts of iron, to an injurious extent, these may be converted into other
insoluble and innocuous bodies, by a sufficient exposure to the air.
Sulphate of protoxide of iron is thus changed into sulphate of peroxide
of iron, which is insoluble, and can therefore exert no hurtful effect
on vegetation, while the soluble organic bodies of peat are oxydized and
either converted into carbonic acid gas, carbonate of ammonia and water,
or else made insoluble.

It is not probable, however, that merely throwing up a well
characterized vitriol-peat into heaps, and exposing it thus imperfectly
to the atmosphere, is sufficient to correct its bad qualities. Such
peats need the addition of some alkaline body, as ammonia, lime, or
potash, to render them salutary fertilizers.

c. _This brings us to the subject of composting_, which appears to be
the best means of tak