the escape of any unpleasant gases, and to keep the material
from adhering to the shovels or the wagon."

"Human urine," said the Doctor, "is richer in phosphoric acid, but much
poorer in nitrogen and potash than the urine from horses, cows, sheep,
and swine."

"Some years ago," said the Deacon, "Mr. H. E. Hooker, of Rochester, used
to draw considerable quantities of urine from the city to his farm. It
would pay better to draw out the urine from farm animals."

"The figures given above," said I, "showing the composition of human
excrements, are from Prof. Wolff, and probably are generally correct.
But, of course, the composition of the excrements would vary greatly,
according to the food."

It has been ascertained by Lawes and Gilbert that the amount of matter
voided by an adult male in the course of a year is--faeces, 95 lbs.;
urine, 1,049 lbs.; total liquid and solid excrements in the pure state,
1,144 lbs. These contain:

Dry substance--faeces, 23-3/4 lbs.; urine, 34-1/2; total, 58-1/4 lbs.
Mineral matter--faeces, 2-1/2 lbs.; urine, 12; total, 14-1/2 lbs.
Carbon--faeces, 10 lbs.; urine, 12; total 22 lbs.
Nitrogen--faeces, 1.2 lbs.; urine, 10.8; total, 12 lbs.
Phosphoric acid--faeces, 0.7 lbs.; urine, 1.93; total, 2.63 lbs.
Potash--faeces, 0.24 lbs.; urine, 2.01; total, 2.25 lbs.

The amount of potash is given by Prof. E. Wolff, not by Lawes and
Gilbert.

The mixed solid and liquid excrements, in the condition they leave the
body, contain about 95 per cent of water. It would require, therefore,
20 tons of fresh mixed excrements, to make one ton of _dry_ nightsoil,
or the entire amount voided by a mixed family of 43 persons in a year.

One hundred lbs. of fresh faeces contain 75 lbs. of water, and 25 lbs.
of dry substance.

One hundred lbs. of fresh urine contain 96-1/2 lbs. of water, and 3-1/2
lbs. of dry substance.

One hundred lbs. of the dry substance of the faeces contain 5 lbs. of
nitrogen, and 5-1/2 lbs. of phosphates.

One hundred lbs. of the dry substance of the urine contain 27 lbs. of
nitrogen, and 10-3/4 lbs. of phosphates.

These figures are from Lawes and Gilbert, and may be taken as
representing the composition of excrements from moderately well-fed
persons.

According to Wolff, a ton of fresh human urine contains 12 lbs. of
nitrogen. According to Lawes and Gilbert, 18 lbs.

The liquid carted from the city by Mr. Hooker was from well-fed adult
males, and would doubtless be