APPENDIX, No. VII. ON THE AGRICULTURAL VALUE OF SEWER AND DRAINAGE WATER.* (See ante, p. 84.) I. House Drainage.-Since the passing of the Public Health Act, about four years since, a very considerable advance has been made in the great sanitary improvements it was intended to advance. It has already been the means of great and invaluable prefatory inquiries and improvements in the drainage of towns, still greater things will be speedily accomplished, greater power will be hereafter given to the general and local boards of health with advantage to the community at large, prejudices will die away, the general health (the poor man's only source of capital) advanced. I propose in this paper, amid all these invaluable contemplated improvements of house drainage, to put in a plea on behalf of the agriculture of our country, for the extended and improved collection and use of the contents of town sewers; a sewage, as at present mismanaged, so generally useless to vegetation, and so pernicious to animal life. To this end I would, in the first place, earnestly and anxiously endeavour to impress upon my readers the public and private duty they have to perform, in aiding in every way in their power the extension of a system of complete sewage, which will not only tend to the health and longevity of their own family circle, but of all their surrounding neighbours. On this branch of the inquiry, a report of their surveyors to the metropolitan commissioners of sewers contains the following passages. They very correctly remark (p. 3), when alluding to the necessity for a general and compulsory system of house drainage, "Though absolute control over house drainage is imperatively necessary, all that is desired is the protection of the public, and this can only be accomplished by making house drainage compulsory under supervision, or, in other words, by the court having power, where no house drainage exists, or where it is defective, to see to its construction or amendment: so that no man may either make his house a fever-nest and common nuisance, by refusing to construct drainage, or make the public sewers the means of spreading * The substance of this paper was, some time since, submitted to my brother commissioners of the metropolitan sewers, and was ordered by them to be printed. It has long been out of print. miasma by connecting with them bad and inefficient works. Thus would that portion of the public who would voluntarily make the provision be secured from the evil consequences that would ensue to them from the neglect of others." The objection sometimes urged against giving the power of a public interference with private property, is well answered by the surveyors; for, when speaking of the present system, they remark— "But can he does he, do as he likes with his own? With defective or deficient drainage he is a very slave in his own house, at the mercy of a host of irresponsible workmen. It is true that he sends for them, but he cannot help himself. It is only when the overflowing cesspool or the choked-up drain is no longer bearable, that this mitigation of the evil is forced upon him, and from year to year is this unwelcome visit repeated. Nor is this all; yet more unwelcome visitors, sickness and disease, force their way in by the same channels in spite of him, and those are happy who escape the most unwelcome visitor of all—death, too often prematurely summoned to these scenes of neglect and apathy." This, however, is a middle and upper class view of the subject. The poor man suffers so immediately-intensely and needlessly suffers from this neglected and anomalous state of things, that he would hail with heartfelt satisfaction the most intrusive interference that would improve the cruel circumstances under which he is thus compelled to exist; but scarcely yet aware of the intimate connexion of his misery with the neglected conditions around him, his voice is not so audible in favour of the change. So great and so constant, indeed, are the evils arising from defective house drainage, that it is a matter of thankfulness that our senses become deadened, and, as it were, acclimatised to the wretched atmosphere with which we are surrounded; for although this state of things engenders a low and depressed condition of existence, and produces a high rate of mortality, it would be still more fatal if we had no tendency to become accustomed to it." I consider, then, the benefits of a systematic and perfect drainage of houses as no longer a doubtful question. Measures are now taking, in many parts of the country, for carrying out the provisions of the Public Health Act. Great good has been already done, and still more valuable operations than any yet contemplated will be soon accomplished. Amid these great efforts, let me urge upon the attention of the constituted authorities the importance of adopting, on all practicable occasions, that arrangement of the drainage of houses which shall afford the greatest facilities for the employment of the sewage for the purposes of irrigation. It is generally practicable to so construct the drains of populous places, that, with a proper attention to the requisite fall, the outlet of these sewers may be so far elevated as to allow of the liquid matter which they discharge being passed over cultivated lands on its way to the adjoining river. Such opportunities as these should on no account be neglected. By the use in this way of the sewage, the land is enriched, the river water less injured in its purity; since, after being employed in water meads, the sewage often flows off the land in a state very nearly colourless. It is not easy to value exactly the matter annually discharged through a town sewer, but still a considerable and very valuable approximation may be made. The most practical way of illustrating my position would be by referring my readers to the cases of the lands so copiously, so extensively, and very profitably irrigated by the contents of the public sewers of Edinburgh, and at Clipstone, close by the town of Mansfield. But another and rather more definite course may be adopted, that which one or two great chemists have followed, to obtain an approximation to a correct estimate. "A thousand pounds of urine," observes Professor Johnston (Elem. Agricultural Chem. p. 158), contains 68 lbs. of dry fertilising matter of the richest quality, worth, at the present rate of selling manures in this country, at least 10s. per cwt. As each full grown man voids about 1,000 lbs. of urine in a year, the national waste incurred in this form amounts, at the above valuation, to 6s. per head. And if five tons of farm-yard manure per acre, added year by year, will keep a farm in good heart, four cwt. of the solid matter of urine would probably have an equal effect; or the urine alone, discharged into the rivers by a population of 10,000 persons, would supply manure to a farm of 1,500 acres, yielding a return of 4,500 quarters of corn, or an equivalent produce of three crops." Of another valuable portion of the heterogeneous contents of a sewer, M. Sprengel, when speaking of nightsoil, remarks (Journ. R.A.S. vol. 1, p. 494), “ Although there can be no doubt that this material is one of the strongest manures, it is still in most places managed with less care than any, and in many altogether neglected; yet the greater or less value attached to it in any country is certainly a proof of the degree in which the agriculture of that country is advanced. Where pains are taken with it, husbandry will be found in other respects excellent; where it is little thought of, the art, in general, will usually be less perfect." It is to the use of this substance, drawn from reservoirs in the towns, that Belgium in a great degree owes her fertility; while in many large cities of Germany it is allowed to drain into the rivers. Since 1,200 lbs. weight of it yearly may be reckoned for each unit of population, it is easy to see, where population is counted by thousands, how important its application must be. The value of the sewage of houses is certainly more generally understood on the continent than with us. In most of the German towns (Johnson on the Fertilisers, p. 107), the householder disposes of the contents of his cesspool for a certain sum of money, besides getting the operation performed gratuitously. By comparing the returns of the different prices paid in those cities for the commodity in question, one year with another, and equalising them by an average price, the inhabitants appear to be benefited to the amount of four francs a head yearly, and the middleman to at least 40 per cent. on the sum he pays to the householder. It is true that these matters in a common sewer are mixed and diluted with a very considerable portion of water; but this is no bar to its use in irrigation (I make the remark more for the use of the general reader than the farmer), since, in the case of water meads, the town sewage is found to be abundantly powerful; so much so, indeed, that in the case of the meadows watered by the sewage of Edinburgh, its strength is sometimes deemed too great; and yet, observes Mr. Stephens, in his valuable" Practical Irrigator," when speaking of these sewer-watered meads, "the grass is let every year by public sale in small patches of a quarter of an acre and upwards, and generally brings yearly from 251. to 30l. per acre." I feel that in these rapid preliminary inquiries I have only employed a few of the many facts in my possession, all tending to prove the same thing. I shall in the following pages gather together more evidence on this national improvement, but in this little section I will only say to the friends of sanitary reform, in all your noble efforts to add health and comfort to the community, to which I bid God speed, do not forget the claims, the demands, and the benefit, of agriculture. II. The Value of Sewage Waters in Irrigation.—An objection is sometimes raised to the use of the sewage of towns for irrigation, that although the substances it contains are very fertilising, yet the proportion in which it is found is too small for its useful employment. The objection then is, that the liquid is very commonly too much diluted with water. Such objectors are not commonly aware of either the pretty uniform strength of the contents of town sewers, the largeness of the mass of rich organic matters which they convey away, or the value of liquid manure to the farmer's crops, in even a far more diluted state than that in which it is found in ordinary periods in the sewer of an English town. In directing, then, our attention to these objects on the present occasion, I feel that we are likely to be labouring in a very useful direction. It is, in fact, in vain to expect the landholder to make any efforts to avail himself of these enriching waters, if he is in doubt as to their fertilising power. |