262 Chronicles of Science. [April, 



perienee of sewage elsewhere, in illustration of the treatment of the 

 sewage of London, we shall have then obtained the only safe guide 

 through the difficulties which surround the subject. And this was 

 what, in the lectures before the Society of Arts and the Agricultural 

 Society of England, was attempted. It was, indeed, subsequently 

 alleged that the analogy of agricultural experience does not lead to 

 the conclusion that it is the best policy to put sewage on grass land in 

 quantity, as in a water meadow. It was declared that the farmer puts 

 on his manure sparingly, carefully calculating how much the crop will 

 pay for, and not applying more. But if agricultural experience 

 proves anything, it proves that plants must be treated according to the 

 nature of them. A rapid succulent growth, which is what we want in 

 grass, is obtained by excessive manuring. The London market-gar- 

 dener applies 60 to 80 tons of solid dung per acre to the cabbage crops 

 of a single year. And it is perfectly consistent with this that the 

 grower of a single acre of Italian rye grass, where succulent growth 

 is also wanted, should put 10,000 tons of sewage on it in the course of 

 a single year. But we are not dependent only on analogy to guide us 

 here : they have for years and generations been putting 10,000 tons 

 of sewage per acre over many hundred acres of poor land near 

 Edinburgh. Here is a case which, as it seems to us, fairly closes the 

 door on any further discussion. If ever there was a satisfactory and 

 conclusive piece of agricultural evidence on the subject it is this — 350 

 acres in extent, and 100 years in duration — it is altogether unassail- 

 able. By the use of sewage in quantity, these 350 acres are made to 

 keep 2,000 cows during the season of growth. They must yield 50 

 tons of grass per acre to do it, or a ton of grass to every 200 tons of 

 the stuff poured on. This, however, the advocates of minimum dress- 

 ings declare to be a poor result. All we know is, that there is nothing 

 like it anywhere else in England ; and taking the character and con- 

 tinuance, as well as the quality of the produce into account, we do not 

 suppose that there is anything like it anywhere else on the face of the 

 earth. Add to this result that which Mr. Lawes observed at Rugby, 

 where the produce was found to be in almost direct proportion to the 

 quantity of the application, and the argument in favour of abundant 

 dressings appears to be irresistible. 



The whole discussion clearly shows that the best chance we have 

 of turning the drainage water of our towns to a profitable agricultural 

 account, rests on the plan which has succeeded at Rugby and at Edin- 

 burgh, where enormous quantities of dilute sewage, already in a putrid 

 state, are poured over a comparatively small area of grass land, Avhose 

 plants, both by leaf and root, feed and flourish !on the ready-made food 

 which is thus continually passing by them. We do not doubt that by- 

 and-by the sewage water of London will be poured over grass lands 

 in Kent and Essex — perhaps over the Maplin Sands, which Messrs. 

 Napier and Hope propose to embank from the sea for the purpose ; 

 and, producing there at the rate of a ton of grass to every 200 tons or 

 thereabouts of the filthy water utilized, we shall thus have food for an 

 immensely increased herd of cows ; and the elements of London 

 sewage will be re-arranged in the more wholesome form of London 

 milk. 



