There is much evidence, however, to prove that it is possible to remove the refuse in such a mode as to avoid the pollution of the river, and at the same time avoid the culpable waste of the most important manure.

A practical example of the money value which lies in the refuse of a town, when removed in the cheapest manner, and applied in the form best adapted to production, viz., by a system of cleansing by water, is afforded in connexion with the city of Edinburgh. In the course of the sanitary inquiry in that city the particular attention of Dr. Arnott and myself was directed to the effects of some offensive irrigation of the land which had taken place in the immediate vicinity of that city. It appears that the contents of a large proportion of the sinks, drains, and privies of that city are conveyed in covered sewers to the eastern suburb of the town, where they are emptied into a stream called the Foul Burn, which passes ultimately into the sea. The stream is thus made into a large uncovered sewer or drain. Several years ago some of the occupiers of the land in the immediate vicinity of this stream diverted parts of it, and collected the soil which it contained in tanks for use as manure. After this practice had been adopted for a long period, the farmers in the vicinity gradually found that the most beneficial mode of applying the manure was in the liquid form, and they conducted the stream over their meadows by irrigation. Others, perceiving the extraordinary fertility thus obtained, followed the example, and by degrees about 300 acres of meadow, chiefly in the eastern parts of that city, but all in its immediate vicinity, and the greater part of it in the neighbourhood of the palace of Holyrood, have been systematically irrigated with the contents of this common sewer. From some of this land so irrigated, four or five crops a-year have been obtained; land once worth from 40s. to 50s. per acre now lets for very high sums. It is stated by a writer cited as an authority, on behalf of the parties interested,—

“That the rent for which some of these meadows are let in small portions to cow-feeders varies on an average from 20l. to 30l. per acre. Some of the richest meadows were let in 1835 at 38l. per acre; and in that season of scarce forage, 1826, 57l. per acre were obtained for the same meadows. * * * The waste land called Figget Whins, containing 30 acres, and 10 acres of poor sandy soil adjoining them, were formed into water meadows in 1821, at an expense of 1000l. The pasture of the Figget Whins used to be let for 40l. a-year, and that of the 10 acres at 60l. Now the same ground as meadows lets for 15l. or 20l. an acre a-year, and will probably let for more, as the land becomes more and more enriched.”

This use of irrigation followed so gradually, that the time of its commencement seems not accurately ascertained, but is known to have been usual near the beginning of the present century. The tanks are still to a certain extent used. The irrigation proceeds from the beginning of April to the middle of September, and, it is supposed that the deposits in the tanks are in the interval increased by the quantity of soil not employed in irrigations.

The practice is strongly objected to by the inhabitants as an offensive and injurious nuisance. To Dr. Arnott, who surveyed the district, the process appeared to be, like most offensive processes, unfitted for the vicinity of a town. The miasma from the preparation of the large accumulations of manure in open receptacles near places of public resort or crowded habitations would probably affect the public health injuriously to a greater or less degree. In particular states of the weather it could scarcely fail to engender disease. In the decomposition of substances for manure, deleterious gasses will be evolved, which in particular states of the atmosphere will act with powerful effects on animal life within their reach. But it is at the same time stated, the process of applying manure by irrigation, that is, separated and diluted with water, is considered to be productive of less deleterious gas, of less injurious effects, than by spreading it over fields in a solid form, and allowing it to remain until it is decomposed and separated by the atmosphere and conveyed into the soil by rain. Liebig, the greatest living authority on agricultural chemistry, states that night-soil loses in drying half its valuable products, that is, half its “nitrogen,” for the “ammonia” escapes into the atmosphere. By irrigation, by the diffusion and conveyance of the manure to the plant in the medium of water the escape of the valuable substance as a noxious and injurious gas is diminished.[[5]] Whatever extent of loss there is from manures by decomposition when placed on the land in a solid form, and when exposed to the action of the atmosphere, it is stated that there is proportionate gain by holding the material in suspension in water. The simple offensiveness, it may be assumed, is a sufficient ground of exclusion of any process from amidst the habitations of a town population. But at a reasonable distance the use of dung or any other manure would not be forbidden; and the process which is the least injurious, the irrigative, is entitled therefore to a preference. Effective drainage must make way for the conveyance of diluted manures, and consequently for effective irrigation.

The continuance of the practice in Edinburgh of the use of the common sewer for irrigation is defended by the occupiers and owners, on the ground that from the time of its commencement, when it was unopposed, and, as it appears to us, escaped any notice, a legal right has been acquired by them in the manure of the city contained in the Burn, and the present claimants of the right contend that they are entitled to compensation under the Scotch law for any diversion of the stream or of the manure which it contains. The irrigation which has surrounded the palace of Holyrood having, as it is considered, rendered it prejudicial to health, Her Majesty’s government, for the protection of this palace as a royal residence, have directed legal process for the trial of the right claimed to the irrigation. The defendants vindicate the measure on the ground of its utility as an agricultural operation, and treat the proposal to divert the contents of the sewers as being in fact a proposal to deprive the city of the milk and butter yielded by more than 3000 milch cows, and the markets of the meat from their carcases; that, in fact, “the grass, which in virtue of irrigation these meadows produce, supports in Edinburgh 3300 cows, and in Leith 600 cows, during the season.”[[6]] We were informed that the parties interested in the lands estimate the compensation that would induce them to discontinue the practice at 150,000l.; and a pamphlet written at their instance, in 1840, states this as the sum which the proprietors of the meadows to the west of the city would be legally entitled to (independently of the claims of those in the east) were the practice abolished by legislative authority. The proprietors have had, on several occasions, sufficient influence to frustrate the efforts of the city authorities, to obtain legislative sanction for the removal of the nuisance, and for a more salubrious disposal of it for the advantage of the inhabitants themselves.

The public refuse of cities by the usual course of legislation in local Acts, and by custom, and on all principles which govern the application of the proceeds of such produce belongs to the public, and it may be submitted that, whatever may be the decision in the case of Edinburgh, means should be taken to prevent for the future the acquisition of new rights at the expense of the health and of the conveniences of such large classes of the population. And it may here be observed that it will probably be found, under the circumstances of the increasing population of the towns, and the increasing necessity of keeping open spaces within and around the towns, and of exercising a general control for the beneficial arrangement of new buildings for the public health and convenience, and of securing convenient public walks and places of temperate and healthful recreation for the population—that it is most desirable for all these objects that means should be taken to redeem to the crown the fee, or otherwise obtain as early as practicable, and on the terms of proper compensation, lands within and in the immediate vicinity of towns for public use.

If then, in Edinburgh, the contents of the cesspools were carried by adequate supplies of water in drains from the houses into covered sewers, and thence in covered instead of open sewers to the lands at proper distances where it might be distributed as manure by irrigation, it would be a mode of irrigation considered by Mr. Smith of Deanston, and other authorities on drainage and irrigation, whom I consulted, the best that is now apparently practicable, i. e., the best means for removing quickly, and constantly, and the least injuriously, the matters which can only remain for removal by any other process at the expense of the public health; they concur in opinion that it would also be the most productive mode of distributing the manure.

On the scale of the value set upon that portion of the refuse of Edinburgh that has been appropriated for irrigation by the occupiers of the land in the vicinity of the city, the value of the whole of the soil of the city (not one-third of which finds its way into the irrigated meadows), if it were made completely available by an appropriate system of town drainage, would be double or treble the amount, producing an income of 15,000l. to 20,000l. per annum for public purposes. On the same scale of value it would appear that, in the metropolis, refuse to the value of nearly double what is now paid for the water of the metropolis is thrown away, partly from the districts which are sewered into the Thames, and partly from the poor districts which are unsewered, where it accumulates and remains a nuisance until it is removed at a great expense. It is allowed by Captain Vetch, an experienced engineer, and by other authorities, to be the most eligible plan in respect to economy as well as efficiency, wherever the levels were not convenient, or it were desirable to send the refuse over heights for distribution, that the contents of the sewers should be lifted by steam power, as water is lifted in the drainage of the fens, and that it might be sent for distribution, wherever it is required for use, in iron pipes, in the same mode as that in which water is conveyed into towns by the water companies. The estimated expense of this mode of cleansing and removal is about the same as the conveyance of water into towns, i. e., not a tithe of the expense of cartage, as will subsequently be shown.

The comparative economy of conveyance of fluid in pipes has been but little observed, and has only recently perhaps been applied for the purpose of cleansing. The following is an instance of the application of the principle:—A contract was about to be entered into by the West Middlesex Water Company for hauling out from their reservoir at Kensington the deposit of eight or ten years’ silt, which had accumulated to the depth of three or four feet. The contractor offered to remove this quantity, which covered nearly an acre of surface, for the sum of 400l., in three or four weeks. The reservoir was emptied in order to be inspected by the engineer and directors before the contract was accepted. It occurred to one of the officers that the cleansing might be accomplished more readily by merely stirring up the silt, to mix it with the water; and then if a cut or outlet were made in the main-pipe used for conveying the water to London, that it might be washed out. He accordingly got thirty or forty men to work in stirring up the deposit, and accomplished the work at the cost of 40l. or 50l. and three or four days’ labour, instead of so many weeks; when the directors went to see the basin, to decide upon the contract, the reservoir was as free from any deposit as a house-floor. Since the discovery thus made, the silt has been regularly cleansed out into the common sewers. It is to be observed, in respect to the relative cheapness of the two modes, that the contractor would only have removed the silt to the nearest convenient place of deposit in the immediate vicinity of the reservoir, whereas, in the fluid state, it might be carried at the actual cost of conveying water, as far as it is at present conveyed, and sold with a profit, 12 or 14 miles, and raised to heights of 150 feet, at 2½d. per ton.