Use of Town Seicar/e as Manure. 
145 
and nvino, supposing? our calculation of the quantity of these 
voided in 24 hours to be correct, we find that ()-10ths of tlie dry 
solid matter, and 5-6ths of the total nitrogen, are present in the 
urine. 
On tlie other hand, if we look to the relative proportion of 
salts valuable in agriculture in tlie two forms of excrement, we 
shall find that the advantage is still greatly in favour of the urine. 
Thus, for instance, in the analysis of faeces by Berzelius, before 
quoted, we find the quantity of salts to be stated as 1'2 per cent., 
so tliat the daily c{uantity (1750 grains) would contain 21 grains 
of salts, whereas in urine the proportion of fixed salts is 7^ parts 
in 1000, which in the three pints (21,000 grains) of urine amounts 
to 158 grains. 
So much for the distribution of manuring matter between the 
solid and liquid excrements, when collected separately and unacted 
on by water or any other agency. But in the actual sewage we 
have further causes of transference of the valuable ingredients 
from the solid to the liquid state. Solid human faeces naturally 
contain incorporated with them all those salts of the food soluble 
as well as insoluble which have not been absorbed into the circu- 
lation in their passage through the stomach and intestines. Some 
of these, and the most important of them, are soluble in water, 
such as the alkaline phosphates and sulphates. Certain soluble 
compounds of nitrogen, and possibly salts of ammonia, exist in 
the mass of human excrements. Both of these classes of sub- 
stances will, therefore, be washed out of the fa?ces when exposed 
to water. 
I have by actual experiment demonstrated the fact of the reduc- 
tion of the percentage of nitrogen in faeces by washing in water. 
Thus three samples of fresh human faeces from different indi- 
viduals were examined in their natural state, and also after being 
macerated in successive quantities of cold water, to remove soluble 
matter ; the samples were of course dried in each case previous 
to analysis. The results given are the actual percentages for the 
dry weights, and, in the case of that portion which has been 
washed, the corrected quantities for the natural condition. 
Percentage of Nitrogen. 
On the Dry Weight. 
On the Natural Weight. 
Faeces in their natural 
state .... 
Ditto after being 
washed with water . 
ABC 
5'81 4-95 6-00 
4-61 4-71 4-21 
ABC 
1-36 1-34 1-49 
1-08 1-27 1-05 
In casting our eyes over these columns, which give the results 
VOL. xv. L 
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