IGO 
Use of Totm Sewage as Manure. 
lime, and I have found in most cases from 30 to 40, and in 
some nearly 60 per cent, of carbonate of lime. The presence 
of tliis quantity of useless matter is not attributable to the undue 
application of the lime, because even if clear lime-water be 
employed the result is the same. It is a necessity of the 
employment of lime in any way for this purpose. 
I have already said that before lime can produce any effect 
in coagulating the sewage, indeed in the act of producing that 
effect, lime neutralizes the free carbonic acid of the sewer-water. 
This carbonic acid is produced in very large quantity by tlie 
fermentation of the sewage ; but even supposing that it were not 
so, the quantity contained in the water supplied to towns would 
materially affect the question. 
Thus the water of London contains, per imperial gallon, in 
round numbers, 15 grains of carbonate of lime dissolved in 
carbonic acid. The addition of free lime to this water in 
neutralizing the carbonic acid produces just 15 grains additional 
of carbonate, so that each gallon of water furnishes a precipitate 
of 30 grains of chalk. 
I have calculated that the excrements of each person in 
London are diluted with or distributed through 20 gallons of 
water, and as when the sewage is precipitated by lime each 
gallon of water furnishes 30 grains of chalk, Ave have 600 grains 
of chalk as the quantity which is added to 437J grains (see page 
144) of solid excrement. So that the manure produced would, 
on this showing, contain nearly 60 per cent, of carbonate of lime. 
This is a startling fact, and one that is well worthy the con- 
sideration of those who are advocating the process. 
I have before stated that Lhave examined many samples of 
manure so prepared. Some of these I do not feel at liberty to 
publish, but in others no such difficulty exists, and the analyses 
of two or three samples are given in a note.* 
* The following are analyses of samples of manure made from London sewage 
hy precipitation with lime ; I am not aware of the price at which the samples 
were offered for sale : — 
Moisture 
Charcoal and organic matter 
Sand, &c 
Oxide of iron and alumina . 
Phosphate of lime . 
Carbonate of lime with a little \ 
carbonate of magnesia 
Sulphate of lime 
Allsaline sulphates and chlorides 
Nitrogen . • 
Equal to ammonia 
No. 1. 
No. 2. 
No. 3. 
4-29 
4-93 
4'75 
36-58 
30-18 
24-37 
9*88 
7'75 
19-44 
1-86 
1'62 
3-51 
5-51 
4-85 
3-73 
■ 32-92 
43-70 
37-55 
8-18 
6-30 
5-56 
0-78 
0-67 
1-09 
100-00 
100-00 
100-00 
1-52 
1-21 
1-91 
1-93 
1 -47 
The 
