April 7, 1870] 
NATURE 
579 
admixture of human excretal refuse with their water, it 
has long been maintained by the local authorities of many 
parts of Lancashire that the evil was less in that district 
than elsewhere, in consequence of the system adopted 
there for dealing with such refuse not affording such 
facility for its discharge into rivers as the water carriage 
system. On this ground the introduction of the water 
system of sewerage has been strenuously opposed. The 
report of the Commission, however, dispels this illusion by 
evidence which is conclusive in proving that the use of the 
old form of closets with ash pits, earth closets, &c., affords 
no protection to rivers. From a long series of analyses 
of sewage from towns where such closets and middens 
are used, it appears that, as compared with the sewage from 
towns where water-closets are used, the composition of 
both are remarkably similar. Besides the nuisance and 
other inconveniences of the dry closet system, it appears 
that the pollution of rivers is but very slightly prevented by 
it. On the other hand, while the advantage gained by that 
system consists merely in the retention of a small propor- 
tion of the excreta in astate to be available for agriculture, 
the treatment to which that portion is subjected renders 
its value as manure very small. Moreover, this is usually 
effected only at the expense of great risk to public 
health, and at a cost which is on the average double the 
money return obtained. The Commissioners, therefore, 
come to the conclusion that the retention of solid excreta 
in middens is not attended with any considerable dimi- 
nution in the strength of the sewage, though the volume 
is somewhat reduced. On that ground they consider it 
hopeless to anticipate any substantial reduction of sewage 
pollution of rivers by dealing only with the solid residue 
of excreta. At the same time they point out the fact that 
the discharge of excretal refuse into rivers is not a neces- 
sary part of the water-closet system. 
As to the influence ef the dry closet system on health, 
the Commissioners refer to the returns of the Registrar- 
General, and to other evidence, as showing that typhoid 
fever, scarlatina, diarrhoea, and other epidemic diseases, 
commit fearful ravages amongst the populations exposed 
to the pestiferous influences it exercises, and they express 
the opinion that to it may be attributed much of the 
responsibility for the high death-rate of South Lancashire | 
towns. They have, however, been unable to obtain con- 
clusive evidence of this owing to the incompleteness of 
the health statistics. They express astonishment at the 
frequent inability of Health Boards to inform them of the 
death-rate in their districts, still less to give information 
as to particular parts of them. 
It is a very general opinion of medical men that the 
presence of an extremely minute amount of organic im- 
purity may, under certain obscure conditions, render 
water unwholesome, and capable of causing or propagat- 
ing disease, especially if that impurity be of animal origin. 
Sewage is the source from which such impurity is most 
likely to originate in a specially dangerous form, and it 
appears the amount capable of causing injury may be so 
small as to have no influence on the outward appearance 
of the water. To the smell, sight, and taste all may seem 
innocuous, and yet there may be present an infinitesimal 
portion of substance rivalling in potency the most viru- 
lent poison, 
That water subject to such contamination is thereby 
rendered unfit for human use, and repugnant to every 
sense of decency, can, it is believed, require no arguments 
to be admitted. That the use of such water is, more- 
over, dangerous and unwholesome, would seem to be sug- 
gested by a knowledge of the changes which excretal 
refuse naturally undergoes, and of the circumstances at- 
tending those changes. The medical officers of Her 
Majesty’s Privy Council, after specially studying numerous 
instances of the outbreak of typhoid fever and cholera, 
have almost invariably found that the prevalence of these 
and other epidemic diseases was accompanied by the use 
of water that had been polluted with drainage from cess- 
pools or sewers. But at the same time it has been im- 
possible to detect or demonstrate, by chemical analysis, 
the presence in the water of anything to which a fatal in- 
fluence or the production of disease can be ascribed. 
This fact, however, does not in any degree, afford a ground 
for regarding the water as free from suspicion. Such 
reasoning would apply with equal force to sewage itself, for 
chemical analysis does not indicate the presence in it of 
anything specially noxious. 
It has indeed often been alleged that if sewage be 
mixed with twenty times its volume of river water, the 
organic matter which it contains will be oxidised com- 
pletely while the river is flowing a dozen miles or so. 
Considering the importance of the subject, it is surprising 
that this assertion, though confidently made in many 
instances, should hitherto have rested upon no more solid 
foundation than mere opinion. But at last the test of 
positive inquiry has been applied by the Rivers Pollution 
Commissioners. The composition of the water of the 
Irwell, the Mersey, and the Darwen at various points in 
the course of these rivers has been ascertained with due 
regard to complications introduced by the influx of unpol- 
luted affluents. The results have shown that when the 
temperature is not above 64° F., a flow of from 11 to 13 
miles produces but little effect upon the organic material 
dissolved in the water. Examination of the gases dissolved 
in water containing an admixture of sewage led to the 
same result. Lastly, experiments devised to augment the 
effect of atmospheric oxidation on such water, so as to 
represent a flow of from 96 to 192 miles in a river at the 
rate of 1 mile an hour, showed that the reduction of organic 
carbon in the water amounted to only 6°4 and 25° per cent., 
that of organic nitrogen to 28°4 and 33°3 per cent., though 
the temperature was 68° F. Thus whether we examine 
the organic pollution of water at different points of a river, 
or the rate of disappearance of the organic material of 
sewage mixed with water and agitated in contact with air, 
or the rate at which dissolved oxygen disappears in water 
polluted with 5 per cent. of sewage, we are in each case 
led to the inevitable conclusion that the oxidation is very 
slow—so slow in fact that it is safe to infer there is no 
river in the United Kingdom long enough to effect the 
complete transformation of sewage in that way. 
These results are further confirmed by evidence as to 
the state of the rivers in the Mersey and Ribble basins ; 
they are consistent with the opinions of chemists, and 
they are opposed only by dogmatic assertions destitute 
of proof. 
To illustrate the extent to which the polluted state of 
Lancashire rivers is a disadvantage to manufacturers, the 
Commissioners state that thirty-nine of the firms who are 
carrying on different branches of trade in the basins of 
the Mersey and Ribble, estimate the benefit they would 
derive if the river water were fit for their use at no less 
than 10,1572. a year, while one calico-printing firm 
estimates the gain to them at 3,000/,a year. The number 
of manufacturers who have given these estimates form 
only a small fraction of the total number in the district. 
MAGNETIC AND SUN SPOT PHENOMENA 
FOR FEBRUARY, 1870. 
(As recorded at the Kew Observatory.) 
O* February 1st about 5 p.m. there occurred a very 
considerable disturbance of the three magnetic 
elements, which lasted until about 2 o’clock in the early 
morning of the next day. The tendency of this disturbance 
was to diminish the declination and the horizontal force, 
while on the other hand the vertical force was increased 
during the first half of the disturbance and diminished 
during the second. The oscillations of the declination 
were very large. The disturbance was accompanied with 
