han 7 tons of straw.

"It would be capital stuff," said the Deacon, "to put in your pig-pens
to absorb the urine. It would make rich manure."

"That is so," said I, "and the weak point in my pig-breeding is the want
of sufficient straw. Pigs use up more bedding than any other animals.
I have over 200 pigs, and I could use a ton of dry muck to each pig
every winter to great advantage. The pens would be drier, the pigs
healthier, and the manure richer."

The Doctor here interrupted us. "I see," said he, "that the average
amount of ammonia in the 33 samples of dry peat analyzed by Professor
Johnson is 2.07 per cent. I had no idea that muck was so rich. Barn-yard
manure, or the manure from the horse stables in the cities, contains
only half a per cent (0.5) of ammonia, and it is an unusually rich
manure that contains one per cent. We are safe in saying that a ton of
dry muck, on the average, contains at least twice as much potential
ammonia as the average of our best and richest stable-manure."

CHAPTER VI.

WHAT IS POTENTIAL AMMONIA?

"You say," said the Deacon, "that dry muck contains twice as much
'_potential ammonia_' as manure?"

"Yes," said the Doctor, "it contains three or four times as much as the
half-rotted straw and stalks you call manure."

"But what do you mean," asked the Deacon, "by '_potential_ ammonia?'"

"It is a term," said the Doctor, "we used to hear much more frequently
than we do now. Ammonia is composed of 14 lbs. of nitrogen and 3 lbs. of
hydrogen; and if, on analysis, a guano or other manure was found to
contain, in whatever form, 7 per cent of nitrogen, the chemist reported
that he found in it 8-1/2 per cent of 'potential' ammonia. Dried blood
contains no ammonia, but if it contained 14 per cent of nitrogen, the
chemist would be justified in saying it contained 17 per cent of
potential ammonia, from the fact that the dried blood, by fermentation,
is capable of yielding this amount of ammonia. We say a ton of common
horse-manure contains 10 or 12 lbs. of potential ammonia. If perfectly
fresh, it may not contain a particle of ammonia; but it contains
nitrogen enough to produce, by fermentation, 10 or 12 lbs. of ammonia.
And when it is said that dry swamp-muck contains, on the average, 2.07
per cent of potential ammonia, it simply means that it contains nitrogen
enough to produce this amount of ammonia. In point of fact, I suppose
muck, when dug fresh from the swamp, contains no amm