rt nitrogen of manures and soils, into nitric
acid, as already stated, is now known to be produced by a minute fungus.
I hope it will be found that we can introduce this _bacterium_ into our
manure piles, in such a way as to greatly aid the conversion of inert
nitrogen into nitrates.

Experiments have been made, and are still continued, at Woburn, under
the auspices of the Royal Agricultural Society of England, to ascertain,
among other things, whether manure from sheep receiving an allowance of
cotton-seed cake is any richer than that from sheep, otherwise fed
alike, but having, instead of cotton-seed cake, the same amount of corn
meal. We know that such manure contains more nitrogen, and other plant
food, than that from the corn meal. But the experiments so far, though
they have been continued for several years, do not show any striking
superiority of the manure from cotton-seed cake over that from corn
meal. I saw the wheat on these differently manured plots in 1879.
Dr. Voelcker and Dr. Gilbert, told me that, one of two plots was dressed
with the cotton-seed manure, and the other with the corn meal manure,
and they wanted me to say which was the most promising crop. I believe
the one I said was the better, was the cotton-seed plot. But the
difference was very slight. The truth is that such experiments must be
continued for many years before they will prove anything. As I said
before, we know that the manure from the cotton-seed cake is richer
in nitrogen than that from the corn meal; but we also know that this
nitrogen will not produce so great an effect, as a much smaller amount
of nitrogen in salts of ammonia, or nitrate of soda.

In going over these experiments, I was struck with the healthy and
vigorous appearance of one of the plots of wheat, and asked how it was
manured. Dr. Voelcker called out, "clover, Mr. Harris, clover." In
England, as in America, it requires very little observation and
experience to convince any one of the value of clover. After what I
have said, and what the Deacon, the Doctor, Charley and the Squire have
said, in the pages of this book, I hope no one will think that I do not
appreciate the great value of red clover as a means of enriching our
land. Dr. Voelcker evidently thought I was skeptical on this point. I am
not. I have great faith in the benefits to be derived from the growth
of clover. But I do not think it originates fertility; it does not get
nitrogen from the atmosphere. Or