408 
Half-a-dozen English Sewage Farms. 
In 1865, again (vol. i., new series), another lecture, delivered 
in the rooms of the Society, was reported, in which Mr. Lawes, 
discussing the results of experiments conducted under a Royal 
Commission at Rugby, warned the authorities of towns that 
whatever value science may put on sewage, it is the agri- 
culturist who has to decide what its real value is ; and this he 
put as low as \d. per ton when delivered on the land. 
In the volume of the ' Journal ' for 1867 (vol. iii., new series) 
there appeared a very complete and candid discussion of the- 
whole subject from the point which a diligent student could at 
that time attain. Estimates of the value of town sewage are based- 
on the fact that 200 ounces of ammonia per annum pass through 
the water-closet from every individual of a population. This is- 
equal to one part of ammonia in every 10,000 parts of the ordinary 
drainage water of our towns, the actual proportion varying with 
the quantity of the water-supply so much as to make 1000 tons 
of it worth as much as from 6 to 16 cwts. of guano (or \d. to 2^6?. 
per ton). The proportion of its other ingredients (potash and 
phosphoric acid) corresponds fairly with that of its ammonia or 
nitrogen to the wants of most of our cultivated plants — that of 
potash, however, being generally deficient. The experience 
of those who have tried — every one unsuccessfully — to realise 
these estimates is also given in the article to which I am re- 
ferring, which has evidently been written by one who has been 
able to apply a very sound judgment to the subject, for the 
general practical conclusions which he deduces from his inquiry 
are trustworthy still. He says (1) that it is only by a liberal use 
of water that the refuse-matters of large populations can be re- 
moved from their dwellings without nuisance or injury to 
health ; (2) that the discharge of town sewage into rivers is both 
mischievous and wasteful, and should not be permitted ; (3) that 
the proper mode of both utilising and purifying sewage is to apply 
it to land ; (4) that though for various reasons it is best applic- 
able to grass, it may nevertheless be occasionally applied with 
advantage to other crops within the area which it commands ; 
(5) that its application to Italian rye-grass, at the rate of about 
5000 tons per acre per annum, is probably the most profitable 
mode of utilisation, but that it is very doubtful whether the 
farmer can afford to pay \d. per ton for it ; (6) that the direct 
result of the general application of town sewage to grass land 
will be an enormous increase in the production of milk, cheese, 
butter, and meat, whilst by the consumption of the grass a large 
amount of solid manure applicable to arable land and crops in 
general will be produced ; and (7) that except when sewage can 
be conveyed to a sufficient tract of suitable land by gravitation, 
towns, so far from making a profit by their sewage, will have to 
