208 
NATURE 
| Dec. 23, 1869 
sufficient area available for disposing of the sewage day by 
day. Innovations of such a kind are exceedingly difficult to 
introduce into an art like agriculture, that is practised so 
much under the influence of tradition and habit ; but, in 
addition to this impediment, there is the more serious one 
of cost to be incurred in adapting a farm for sewage 
irrigation. For the farmer, the value of town sewage is 
to be estimated, not by the intrinsic worth of the substances 
it contains, but by the amount of those substances which 
are effective, or at least likely to be effective, in augmenting 
the produce of his land after due allowance for the in- 
fluence of season. If sewage containing in each ton 
twopence-worth of manure be applied to land in such 
proportion that only one-fourth of the aggregate quantity 
of manure constituents remain in the land or become 
effective, then the sewage so applied cannot be worth 
more than one-halfpenny per ton to the farmer. 
It is therefore futile to estimate by calculation, as has 
often been done, the value of the sewage discharged from 
a town, and to anticipate, on such a basis, the possibility 
of making the sewage a source of considerable revenue to 
the town. Speculations of this kind have naturally even- 
tuated in disappointment and the disgust of all who have 
been misled by them, without making due allowance for 
the drawbacks that influence the value of sewage as 
manure even more than the intrinsic worth of its con- 
stituents. 
Another circumstance to be taken into account in this 
respect is the outlay requisite for conveying sewage from 
the sewer outlets where it is discharged from a town to the 
land where it can be utilised as manure. Even under the 
present system of agriculture, farmers would often be glad 
to have the command of town sewage for application to 
their land during dry seasons, when the total failure of a 
crop might be thus obviated. But it rarely happens that 
this is practicable, owing to the want of any channel of 
communication between the sewer outlets and the land 
where it would be useful. Farmers, and even landowners, 
would rarely be in a position to incur the expense of 
making such communications, and municipal authorities 
refuse to do it as being beyond their province. However, 
if the importance of preventing the pollution of rivers 
and watercourses were fully appreciated in regard to its 
influence on public health, there is much reason to believe 
that the obligation of getting rid of town sewage apper- 
taining to municipal bodies really extends far beyond 
merely discharging it into a neighbouring stream, and 
involves a considerable contribution on their part, accord- 
ing to local conditions, towards the outlay necessary for 
combining the attainment of their special object with that 
of the farmer by getting rid of the sewage in such a 
manner that it may be made useful. 
It would, at present, be almost impossible to suggest 
how this object should be realised ; for if town sewage is 
to be applied on the same principle as manure like guano 
or bones, only in such proportion as to give the requisite 
dressing of manure constituents per acre of land, the area 
over which the sewage of a large town would have to be 
distributed would be enormous, and the attendant expenses 
of its distribution would be very large. If, on the other 
hand, the area of land to which the sewage is applied be 
limited so as to dispose of the largest possible proportion 
of sewage and keep the cost of arrangements for distribu- 
tion within the smallest bounds, there would generally be 
such a disproportion between the actual quantity of manure 
constituents applied per_acre and the possible effect pro- 
duced on the produce of the land, that the value of the 
sewage as manure would be greatly diminished ; or, in 
other words, very much of it would be wasted, and still 
simply got rid of. 
Here again sanitary considerations demand attention, 
and the possible influence which the application of town 
sewage to land may have on the public health must be 
taken into account, It is, for instance, indispensable that 
the use of town sewage in agriculture should be conducted 
in such a way as to be an effectual remedy for that pollu- 
tion of rivers which has become a serious national evil. 
Moreover, if sewage-irrigated farms are to be distributed 
throughout the country in the neighbourhood of towns, it 
is still more imperative to know that the adoption of this 
course will not be productive of injury to the public health. 
This point should receive the fullest elucidation before any 
general measures can be taken with the object of utilising 
town sewage, and the conditions under which that can be 
effected without risk should be thoroughly investigated. 
Such an inquiry would comprise many questions of 
detail, requiring varied skill, and considerable time as well 
as labour, for its prosecution ; and the British Association 
Committee that contemplates carrying it out, impressed 
with the magnitude and importance of the task, has felt 
the necessity of much larger means for conducting the 
inquiry than that small sum which the Association were 
able to grant for the purpose of meeting the expenses of 
preliminary work. If municipal bodies and landowners 
respond to the application of the Committee in a manner 
commensurate with their interest in this subject, and pro- 
vide adequate funds for thorough investigation, there is 
reason to expect some considerable step will have been 
made towards placing the question of sewage disposition 
and utilisation in a more satisfactory position than it has 
yet attained. 
Besides the main points already mentioned, of getting 
rid of sewage and turning it to account, there are yet 
other questions of moment to be considered. ‘The rapid 
adoption of reformatory methods, in regard to the sanitary 
state of towns, which has marked the past quarter of 
a century, has not always been attended with so much 
improvement as might have been desired. In some 
instances, serious anomalies have presented themselves 
in this respect, and there is much reason to believe that 
circumstances yet remain to be provided for which affect 
the sanitary state of towns. Mr. Bailey Denton has 
recently called attention to this matter by pointing out in 
his letters to the 7zzes the fact that, in some instances, 
the sewerage works of towns have been constructed in 
such a way as to admit of the soil surrounding the sewer 
being permeated by sewage, and he has suggested, as a 
possibility deserving of inquiry, that in this way an effect 
may be produced similar to the infiltration of house 
refuse from cesspools into the surrounding soil. If such 
be the case, it would perhaps account for the fact that 
in some towns, where every kind of known sanitary 
precaution has been taken, the reduction of disease and 
mortality has been but slight. Such an action, though 
slower than in the case of infiltration from cesspools, 
would not be less sure in its influence on the sanitary 
