have been rendered soluble during the
fermentation of the manure.

"There are more insoluble phosphates in the rotted manure than in the
fresh, but we do not conclude from this fact that any of the phosphates
have been rendered insoluble during the process of fermentation--neither
are we warranted in concluding that any of them have been rendered
soluble, simply because we find more soluble phosphates in the rotted
manure."

"Very true," said the Doctor, "but it has been shown that _in the heap_
of manure, during fermentation, there was an _actual increase_ of
soluble mineral matter during the first six months, and, to say the
least, it is highly probable that some of this increase of soluble
mineral matter contained more or less soluble phosphates, and perhaps
Dr. Voelcker had some facts to show that such was the case, although he
may not have published them. At any rate, he evidently thinks that the
phosphates in manure are rendered more soluble by fermentation."

"Perhaps," said I, "we can not do better than to let the matter rest in
that form. I am merely anxious not to draw definite conclusions from the
facts which the facts do not positively prove. I am strongly in favor of
fermenting manure, and should be glad to have it shown that fermentation
does actually convert insoluble phosphates into a soluble form."

There is one thing, however, that these experiments clearly prove, and
that is, that there is a far larger quantity of _soluble_ phosphates in
manure than is generally supposed. Of the total phosphoric acid in the
fresh manure, 43 per cent is in a soluble condition; and in the rotted
manure, 40 per cent is soluble.

This is an important fact, and one which is generally overlooked. It
enhances the value of farm-yard or stable manure, as compared with
artificial manures. But of this we may have more to say when we come to
that part of the subject. I want to make one remark. I think there can
be little doubt that the proportion of soluble phosphates is greater in
rich manure, made from grain-fed animals, than in poor manure made
principally from straw. In other words, of 100 lbs. of total phosphoric
acid, more of it would be in a soluble condition in the rich than in the
poor manure.

CHAPTER XVIII.

HOW THE DEACON MAKES MANURE.

"I think," said the Deacon, "you are talking too much about the science
of manure making. Science is all well enough, but practice is better."

"That depends," said