“You find then, in Thames water, about the bridges, things decidedly connected with the sewer water, as vegetable and animal matter in a state of decomposition?” “I do; about the bridges, and in the neighbourhood of London, there is very little living vegetable matter on which animalculæ could live; the only source of supply which they have is the organic matter contained in sewer-water, and which is to be regarded as the food of these creatures. Where infusoria abound, under circumstances not connected with sewage, vegetable matter in a living condition is certain to be met with.”
Respecting the uses of the sewage, I may add the following brief observations. Without wishing in any way to prejudice the question (indeed the reader will bear in mind that I have all along spoken reprovingly of the waste of sewage), I am bound to say that the opinions I heard during my inquiry from gentlemen scientifically and, in some instances, practically familiar with the subject, concurred in the conclusion that the sewage of the metropolis cannot, with all the applications of scientific skill and apparatus, be made either sufficiently portable or efficacious for the purposes of manure to assure a proper pecuniary return. In this matter, perhaps, speculators have not traced a sufficient distinction between the liquid manure of the sewers and the “poudrette,” or dry manure, manufactured from the more solid excrementitious matter of the cesspools, not only in Paris, but, until lately, even in London, where the business was chiefly in the hands of Frenchmen. The staple of the French “poudrette” is not “sewage,” that is, the outpourings of the sewers—for this is carried into the Seine, and washed away with little inconvenience, as the tide hardly affects that river in Paris; but it is altogether “cesspoolage,” that is, the deposit of the cesspools, collected in fixed and moveable utensils, regulated by the “universal” police of Paris, and conveyed by Government labourers to the Voirées, which are huge reservoirs of nightsoil at Montfauçon, about five miles, and in the Forest of Bondy, about ten miles, from the centre of Paris. The London-made manure also was all of cesspoolage; the contents of the nightman’s cart being “shot” in the manufacturer’s yard; and when so manufactured was, I believe, without exception, sent to the sugar-growing colonies, the farmers in the provinces pronouncing it “too hot” for the ground. The same complaint, I may observe, has been made of the French manufactured cesspool manure. I heard, on the other hand, opinions from scientific and practical gentlemen, that the sewer-water of London was so diluted, it was not profitably serviceable for the irrigation of land. All, however, agreed that the sewage of the metropolis ought not to be wasted, as it was certain that perseverance in experiment (and perhaps a large outlay) were certain to make sewage of value.
The following results, which the Board of Health have just issued in a Report, containing “Minutes of Information attested on the Application of Sewer-water and Town Manures to Agricultural Production,” supply the latest information on this subject. The Report says first, that “to be told that the average yield of a county is 30 bushels of wheat per acre, or that the average weight of the turnip crop is 15 tons per acre, means very little, and there is little to be learned from such intelligence; but if it is shown that a certain farm under the usual mode of culture yielded certain weights per acre, and that the same land, by improved applications of the same manure, by the use of machinery, and by employing double the number of hands, at increased wages, is made to yield four fold the weight of crop and of better quality than was previously obtained, a lesson is set before us worth learning.”
It then proceeds to cite the following statements, on the authority of the Hon. Dudley Fortescue, as to the efficiency of sewage-water as a liquid manure applied to land.
“The first farm we visited was that of Craigentinney, situated about one mile and a half south-east of Edinburgh, of which 260 Scotch acres” (a Scotch acre is one-fourth more than any English acre) “receive a considerable proportion of such sewerage as, under an imperfect system of house-drainage, is at present derived from half the city. The meadows of which it chiefly consists have been put under irrigation at various times, the most recent addition being nearly 50 acres laid out in the course of last year and the year previous, which, lying above the level of the rest, are irrigated by means of a steam-engine. The meadows first laid out are watered by contour channels following the inequalities of the ground, after the fashion commonly adopted in Devonshire; but in the more recent parts the ground is disposed in ‘panes’ of half an acre, served by their respective feeders, a plan which, though somewhat more expensive at the outset, is found preferable in practice. The whole 260 acres take about 44 days to irrigate; the men charged with the duty of shifting the water from one pane to another give to each plot about two hours’ irrigation at a time; and the engine serves its 50 acres in ten days, working day and night, and employing one man at the engine and another to shift the water. The produce of the meadows is sold by auction on the ground, ‘rouped,’ as it is termed, to the cow-feeders of Edinburgh, the purchaser cutting and carrying off all he can during the course of the letting, which extends from about the middle of April to October, when the meadows are shut up, but the irrigation is continued through the winter. The lettings average somewhat over 20l. the acre; the highest last year having brought 31l., and the lowest 9l.; these last were of very limited extent, on land recently denuded in laying out the ground, and consequently much below its natural level of productiveness. There are four cuttings in the year, and the collective weight of grass cut in parts was stated at the extraordinary amount of 80 tons the imperial acre. The only cost of maintaining these meadows, except those to which the water is pumped by the engine, consists in the employment of two hands to turn on and off the water, and in the expense of clearing out the channels, which was contracted for last year at 29l., and the value of the refuse obtained was considered fully equal to that sum, being applied in manuring parts of the land for a crop of turnips, which with only this dressing in addition to irrigation with the sewage-water presented the most luxuriant appearance. The crop, from present indications, was estimated at from 30 to 40 tons the acre, and was expected to realize 15s. the ton sold on the land. From calculations made on the spot we estimated the produce of the meadows during the eight months of cutting at the keep of ten cows per acre, exclusive of the distillery refuse they consume in addition, at a cost of 1s. to 1s. 6d. per head per week. The sea-meadows present a particularly striking example of the effects of the irrigation; these, comprising between 20 and 30 acres skirting the shores between Leith and Musselburgh, were laid down in 1826 at a cost of about 700l.; the land consisted formerly of a bare sandy tract, yielding almost absolutely nothing; it is now covered with luxuriant vegetation extending close down to high-water mark, and lets at an average of 20l. per acre at least. From the above statement it will be seen how enormously profitable has been the application in this case of town refuse in the liquid form; and I have no hesitation in stating that, great as its advantages have been, they might be extended four or five fold by greater dilution of the fluid. Four or five times the extent of land might, I believe, be brought into equally productive cultivation under an improved system of drainage in the city, and a more abundant use of water. Besides these Craigentinney meadows, there are others on this and on the west side of Edinburgh, which we did not visit, similarly laid out, and I believe realizing still larger profits, from their closer proximity to the town, and their lying within the toll-gates.”[67]
Such, then, are said to be the results of a practical application of sewer-water. The preliminary remark of the Board of Health, however, applies somewhat to the statement above given; for we are not told what the same land produced before the liquid manure was applied; nor are we informed as to the peculiar condition and quantity of the land near Craigentinney, and how it differs from the land near London.
The other returns are of liquid manures, of which sewer-water formed no part, and, therefore, require no special notice of them. The following observations are, however, worthy of attention:—
“The cases above detailed furnish some measure of the possible results attainable in cultivation, especially corroborated as they are by others which did not on this occasion come under our personal observation, but one of which I may mention, having recently examined into it, that of Mr. Dickinson, at Willesden, who estimates his yield of Italian rye-grass at from 80 to 100 tons an acre, and gets 8 or 10 cuttings, according to the season; and as there is no peculiar advantage of soil or climate (the former ranging from almost pure sands to cold and tenacious clays, and the latter being inferior to that of a large proportion of England) to prevent the same system being almost universally adopted, they give some idea of the degree to which the productiveness of land may be raised by a judicious appliance of the means within our reach. When it is considered that such results may, in the vicinity of towns and villages, be most effectually brought about by the instant removal of all those matters which, when allowed to remain in them, are among the most fruitful sources of social degradation, disease, and death, one cannot but earnestly desire the furtherance of such measures as will ensure this double result of purifying the town and enriching the country; and as the facts I have stated came at the same time under the notice of the gentleman I mentioned above, under whose able superintendence the arrangements for the water-supply and drainage of several towns are now in course of execution, I trust it will not be long before this most advantageous mode of disposing of the refuse of towns may be brought into practical operation in various parts of the country.
“I have, &c.,
“D. F. Fortescue.
“General Board of Health.”