404 
Sewage-Farming. 
than 40/. or 50Z. an acre, an outlay, however, in that case amply 
repaid. At Bedford (a successful example of sewage-farming), 
it did not exceed lOZ. per acre, including covered earthenware 
carriers. It will probably be found, where suitable land is 
selected, to range from 10/. to 20Z., and to average 15/. per acre. 
This sum will not include the conveyance of sewage to the 
farm, nor the erection of pumping machinery for its elevation 
to the height requisite for its distribution. 
Extent of Land requieed. 
The quantity of land required for the disposal of all the sewage 
of a town should be a serious consideration; and the farmer will 
be wise to provide land according to the estimated increase of the 
population. He will, however, have very considerable difficulty 
in deciding at the present time upon the acreage of land which 
ought to be put under sewage. For the -purification of the sewage 
has been hitherto far more studied than its utilization. This 
fertilizer, of which we are beginning at last to understand the 
true value, has hitherto been treated as waste, and much land 
has been occupied simply for the purposes of filtration. The 
capacity of the soil in this respect is well-nigh unlimited. 
The Rivers Pollution Commissioners give it as their opinion, 
that 5 acres of land, drained 6 feet deep and thoroughly 
well, will suffice for the purification of the sewage of 10,000 
persons, if it be only divided into equal plots, each of which 
shall receive the sewage of six houses. The object of the 
sewage-farmer will be, of course, to spread it over the largest 
area compatible with remuneration ; the prevention of waste 
and the extraction of nitrogen will be his chief cares. Hope- 
less, indeed, may he be of the realization of any pecuniary result 
should he select such a farm as Barking for his model. At 
that place, if Mr. Morgan's method of calculation be reliable, 
the sewage of no less than 335 persons was poured over every 
acre in 1870. The opinions of practical men now point, how- 
ever, to 50 or 60 as the number of persons who can beneficially 
contribute to each acre. As a matter of fact, at least double 
that number yield ammonia to most of our sewage-farms. At 
Croydon 100, at Bedford 140, at Banbury 80, and at Aldershot 
80 individuals thus contribute ; but Mr. Hope, with the light of 
recent experience, descending from 50 to 40, from 40 to 30, and 
from 30 to 20, is now strongly of opinion that the latter number 
represents something like the normal proportion of human beings 
whose sewage should be disposed of per acre ; and for this simple 
reason, that he is sanguine enough to believe that by proper 
management the whole of the nitrogen derived from such a 
