152 
Use of Town Seicar/c as Manure. 
The appearance of London sewage-water, as it issues from 
the mouths of the sewers into the Thames, is very different from 
what most people imagine, and by no means so repulsive. The 
great distance which it has, on the average, to flow over a rough 
surface, the angles it has to turn, and the immense iriction 
and agitation derived from these circumstances, form together 
the most perfect means of its disintegration. So that, on its 
arrival at the mouth of the sewers, no visible trace of its origin 
is to be detected. A glass jar of London sewage at the outfall 
is only a slightly turbid liquid, with a flocculent, slimy, fibrous 
matter floating through it. It has a putrid smell, though by no 
means so bad as would be expected, — the chief odour being that 
of sulphuretted hydrogen. The great nuisance of all sewage 
when thrown into rivers and watercourses (and I do not wish 
to underrate it) is the accumulation of the solid matter which 
takes place on the banks of such streams, and which, in its de- 
composition, is always giving out noxious exhalations ; the 
liquid itself, when mixed with a large body of water, is too 
diluted to give off any very great smell. 
London sewage has this in peculiar from that of most other 
towns (except a few of those that most nearly approach it in 
size), that it is in a very forward state of decomposition. It can 
never be said of any samples collected at the mouth of the 
sewers, that it is the product of tlie day or even the week before, 
and for this reason, amongst others, that in the sewers immense 
deposits of the solid matters are occurring, which remain there 
a considerable time, and, by their decomposition, are always 
more or less influencing the composition of the liquid which 
flows over them. These deposits are sometimes on an enormous 
scale, and as they cannot be economically removed from the 
sewers by the ordinary process of " flushing," the solid soil is 
dug out and removed. 
Independently of this circumstance, the distance which the 
sewage has to flow, as was before mentioned, tumbled about in 
free contact with air — for the sewers are of a capacity much 
greater than the average flow — precludes the possibility of the 
materials reaching the outfall in anything like a fresh state. 
To prevent the necessity of reference, I subjoin the analyses of 
two samjiles of London sewer-water, which have already appeared 
in the pages of this Journal. The samples were supplied to me 
by the Commission of Sewers at the request of the General 
Board of Health, — one of them being taken from a sewer in 
Dorset-square and tlie other in a place called Barrett's-court : — 
The matter in suspension and that in solution were separately 
analyzed — the following was the quantity of each in an imperial 
gallon of the specimens : — 
