tity of sewage to apply to the land. Of the 40 acres of land belonging to the school, four acres were under Italian rye grass and 12 acres were in very poor meadow—indeed, the whole estate was a stiff London clay, very adverse to good cultivation. A tank containing 12,000 gallons of sewage was erected to work this land. The rye-grass of four acres was dressed by hose and jet six different times in the year, the whole amount being about 1500 tons of sewage per acre; and the produce of these four acres fed “16 large dairy cows, one bull, and three or four head of young stock, besides three farm horses, for the summer months, or 180 days; each cow yielding on an average throughout the year eight quarts of milk per day. There was no perceptible difference in the crop over the whole four acres, all of it being as thick as it was possible for grass to stand. Therefore, taking that part irrigated with the hose and jet as keeping 10 of the cows, the produce could not have been less than 70 tons of green food to the acre every season. I believe it is generally considered that one of the large half-bred short-horn cows, giving full milk, will eat at least 1½ cwt. of green meat per day; allowing 8d per gallon for the milk thus produced, it would give 120l. as the return from these two acres, and, without deducting the expenses, 9d. per ton for every ton of sewage used. Assuming that this sewage had been delivered on the farm by a company, and charged 2d. per ton, the landlord or tenant having laid down the pipes on the farm necessary for its distribution, the expenses would stand as follows:—1500 tons of sewage per acre, at 2d. per ton, 25l.; one lad, distributing for 12 days, 12s.; rent of two acres, at 25s., 2l. 10s.; half man’s time cutting grass, milking, &c., &c., 7l. 10s.; part time of horse and cart, carting grass to sheds, 3l.; interest on cost and wear of pipes, hose, &c., 16s.: making a total of 39l. 8s., which, deducted from the 120l., would leave 80l. 12s. as the net profit upon those two acres, supposing that no other deductions had to be made for keeping the stock in the winter time.” When we hear a witness talk of producing seventy tons of green food per acre in one season, it seems so much like romancing, that we have thought it well to give his own words, and to state that, in the opinion of the Select Committee, they are entitled to “very great weight.” It must be stated, that of these four acres of rye-grass two were allowed an unlimited amount of sewage, amounting to between 8000 and 9000 tons per annum; yet they did not yield a better result than the other two acres dressed with only 1500 tons of sewage throughout the year, giving, in the words of the Select Committee, “a most conclusive proof of the uselessness of the enormous dressings recommended by some of the witnesses.” And, we may observe, not only the “uselessness” but the perniciousness of such superfluous dressings; for Mr. Westwood proves that the meadow grass, which was irrigated on the catch-water system at the rate of 9000 tons an acre, threw its sewage off by the drains almost unaltered in colour, and so strong that he thought it necessary to filter it before it flowed away into the brook, lest an action should be commenced against the institution for polluting the public watercourse. He found that the knobs of grass which lay above the general level of the field flourished quite as much as those that received the whole flow of the sewage; and he concludes that the dressings of 300 tons, once in the spring and once after cutting the first crop, would be equally effective with the largest dressings. The settlement of the question—heavy versus light dressings—is of great importance for other reasons besides the fertilisation of the land. To say nothing of the pumping expenses it will save, there is the question of keeping our water-sources pure: a matter which cannot be insured if enormous quantities of sewage were to be pumped on to the land to find its way down in a polluted state to the springs. We do not doubt that within certain limits the value of sewage-manure dressings will depend upon the degree of its dilution. A certain quantity of water is absolutely necessary to carry the fertilising particles to the roots of the plants; but what that precise quantity is we have yet to find out. Owing to the ever-varying amount of rainfall which is allowed to dilute it, no exact calculations can be made of its value—indeed, the excreta of each person are estimated by two individuals in the report variously at 1s. 9d. to 1l. per annum: a divergence which results from the absurd practice of allowing the rainfall to mix with the house sewage, which would otherwise be represented by a tolerably invariable quantity to each inmate. The evidence of Lord Essex, who has used the sewage manure extensively, is to the effect that it is applicable to all crops, and that it may be applied with advantage at all times of the year, excepting during hard frosts; but that it is expedient that the agriculturist should have the full command of the sewage, so that he may apply it when and in what quantities he likes. This points to the system of irrigation by pipes and hose and jet as the most convenient method of distribution. Mr.; Tufnell, one of Her Majesty’s Inspectors of Schools, who reports with respect to the rigid exactitude of the experiments carried on at the Anerly schools under his inspection, states that he found the second crop produced by the sewage was far more productive than the second crop produced by guano, a statement which accords with the assertion of all scientific agricultural chemists, that while guano and other manufactured manures exhaust the soil by over-stimulation, sewage manure permanently improves it.
We trust this statement will restore confidence to those who have been frightened by a letter in the “Times” lamenting the exhaustion of our vegetable mould under its guano treatment, and also the following remarks of the Committee, which will, doubtless, give a clue to the extraordinary evidence of chemists and others interested in the sale of foreign manures:—
If the sewage of our cities and towns were utilised to the best advantage over suitable areas, it is evident that, as on the Court farms, little or no imported manufactured manures would be used; this would greatly limit the area now supplied by such manures, and would therefore reduce the profits of all those engaged in the importation, manufacture, or sale of manure.
