48 
THE P14 ABM A CEXJTIC A L JOURNAL. 
[July 16, 1870. 
the sewage of the London district, and that, as it passed 
lower down, the oxygen was again absorbed from the 
air, and again it became diluted with a large volume of 
water from below, from other sources—the Lea, the 
Lavensbourne, and other tributaries—and in this man¬ 
ner the water had again become oxidized. I look,” he 
says, “ upon this as a direct proof of the effect of oxygen in 
destroying those organic contaminations which are thrown 
into the river'' 1 Dr. Odling, also, in reply to a question 
from the Loyal Commissioners, as to the self-purifying 
power of water said, “ You see in many rivers, even slug¬ 
gish rivers, having sewage discharged into them, that 
for a mile or two the appearance of the river is affected 
by the sewage, but beyond a certain distance there is no 
recognizable effect at all—the weeds are perfectly clean 
and perfectly healthy; ” and he instances the river Soar, 
at Leicester, which is black and very foul from the re¬ 
fuse of the town; but “three miles from the town its 
appearance is such that you could not tell it had been 
contaminated, for it was running clear, with fish swim¬ 
ming in it, and the weeds were clean.” That, he said, 
was simply from a process of self-purification. Again, 
Dr. Taylor, of Guy’s Hospital, in his examination before 
a Committee of the House of Commons on the Metropolis 
"Water Supply Bill, states, when speaking of the effect 
of water on sewage matter, that “all such substances 
are very rapidly decomposed and destroyed; the nitro¬ 
gen is converted into nitric acid, and the sulphur into 
sulphuric acid, so that those fetid and putrid substances 
which go into the Thames from London, when rolled 
about by the action of the water, containing an enormous 
amount of air, are all oxidized and destroyed; within a cer¬ 
tain limit they may be found , but still , after a very short 
passage , they are very soon indeed destroyed. I believe,” 
he says, “it is the opinion of every chemist who has con¬ 
sidered the subject, that sewage matter docs not remain 
as sewage matter in well-aerated water, but all phos¬ 
phorus, sulphur, and nitrogen are speedily destroyed by 
the oxygen of the water. Every 1000 gallons of water 
contain 48 gallons of oxygen, and that oxygen destroys 
all such putrescent effluvia. "With water not exposed to 
the air, and not containing air, it is most offensive and 
mi wholesome; but with water containing air, like the 
Thames, and exposing an enormous surface to the air in 
its daily motion, the effect is completely to obliterate 
every trace (of sewage matter) that a chemist can detect. 
In the Thames, and other water, the air is in a state of 
solution, the matter in a state of diffusion, and thus the 
air and this fetid matter are in the very condition to 
combine together and form an innoxious compound; it 
requires time and motion, but still it does take place with 
very extraordinary rapidity.” And ho concludes his re¬ 
marks by saying, “ The supposition that the drainage of 
London,'which goes into the river about the bridges, re¬ 
mains the drainage of London all up the river, is con¬ 
trary to all chemical experience; it is contrary to every 
chemical fact, and every chemical analysis.”* 
In a former communication to you I spoke of the in¬ 
vestigations of Dr. Angus Smith on the polluted water 
of the Clyde, which were to the same effect. Engineers 
also, who' have been largely concerned in such inquiries, 
have always spoken of the remarkable self-purifying 
power of water. Mr. Hawksley, whose experience of 
this matter renders him a very high authority on the 
subject, said, in answer to a question from the Livers 
Commission, as to the quantity of water, compared with 
the volume of sewage discharged mto it, as necessary for 
the purpose of breaking up the sewage into inoffensive 
compounds, that generally 20 to 1 was sufficient; but if 
the water flows rapidly, and is very much disturbed, so 
* The supposition here referred to is an imaginary one, 
that no chemist would entertain. Whatever change sewage 
may undergo after its discharge into rivers, there is no evi¬ 
dence to show that it is destroyed so rapidly or to such extent 
as to be harmless; and that is the real point to be considered. 
as to be continually receiving fresh oxygen, a smaller 
quantity—even 12 to 1—will effect the process; and if 
it proceeds very tardily it may take a little more, but 
20 to 1 is abundant. “I could,” he adds, “give you 
very remarkable instances of it. Take Sheffield. Nothing 
can be fouler probably than the state of the water at 
Sheffield, whereas if you go down to Doncaster (about 
twenty miles below Sheffield), the water is supplied by 
the water-works, and is actually drunk in the town.” 
Again, says Mr. Hawksley, “ Take the river Irwell (the 
very river which Dr. Erankland has been examining). 
After leaving Manchester it receives the Irk, the Mat- 
lock, and all the refuse of the manufacturing population 
for a great many miles; when it travels down only eight 
or nine miles to Warrington it is perfectly changed; it 
ceases, or nearly ceases, in that short distance, to be an 
offensive river.” “At Leicester, likewise,” to use his 
words, “ the water was as black as ink—nothing would 
live in it, and the smell was abominable; but by the time 
it had got to Loughborough (which is about twelve miles 
below Leicester) it was entirely restored to its pristine 
condition. You could stand on the bridge there and see 
the fish swimming amongst the beautiful reedy and other 
plants growing in the water, just as in the purest stream. 
You could see every pebble at the bottom; that is an in¬ 
stance of oxidation.” You may remember the instance 
which I gave you last year of the river Trent, which re¬ 
ceives the sewage and manufacturing refuse of some of 
the largest, busiest, and dirtiest towns hr the kingdom, 
with an aggregate population of more than a million and 
a half of persons, and yet when it arrives at Nottingham 
it is not only clear, pellucid, and inoffensive, with abund¬ 
ance of fish and aquatic plants, but is actually used for 
the domestic supply of the town. But why need I mul¬ 
tiply such instances, or dwell upon such self-evident em¬ 
pirical facts, when they are within the common know¬ 
ledge and experience of everybody? for even Dr. Erank¬ 
land is ready to admit, in the case of the London water 
supply, that “by gradual oxidation, partly in the pores 
of the soil, partly in the Thames and its tributaries, and 
partly in the reservoirs, filters, and conduits of the com¬ 
pany, this sewage contamination had been converted into 
comparatively innocuous organic compounds before its 
delivery to consumers.” 
“ I believe,” said Dr. Frankland, in his evidence before 
the Loyal Commission on Water Supply, “that the 
noxious part in sewage is that which is held in mecha¬ 
nical suspension, not that in solution;” and no doubt 
the sedimentary matters of sewage are capable of pro¬ 
ducing an offensive condition of the rivers, for w T hen 
they are discharged into a sluggish stream they quickly 
subside, and form accumulations of persistently putrefy¬ 
ing mud. This is the chief cause of complaint w y herever 
sewage enters a river. 
At the time of the inquiry into the state of the Thames, 
in 1858, it was admitted on all hands that the filthy mud- 
banks of the river were the great source of annoyance; 
and Dr. Hofmann and Mr. Witt, in their report of the 
matter to the Government referees, declared emphatically 
that the formation of this mud-deposit in the bed of the 
river appeared to them to be by far the most serious evil 
which results from the discharge of London sewage into 
the river, and they strongly urged this point upon public 
attention. Dr. Odling, in his report to me on this sub¬ 
ject, for the information of the referees appointed by the 
Metropolitan Board of Works, said that “any means 
which would prevent the deposition of organic mud in 
the bed, but more particularly on the exposed banks of 
the river, w r ould effect an amply sufficient purification of 
it.” The same was my own opinion, for in reporting to 
the referees I stated that the mischief produced by the 
discharge of sewage into the river ‘ ‘ was not occasioned, 
as I once supposed, by the soluble matters of the sewage, 
but by the mud or insoluble constituents which settle 
and putrefy upon the banks of the river.” These con¬ 
stituents being in a solid form, and not easily accessible 
