with the stubborn obstacle of perpetual procrastination. Having now cleared our ground by the discussion of the two preliminary questions relating to the pollution of the Thames and the value of the sewage, we shall proceed to offer a few suggestions in reference to the several plans which have been put forward, or are likely to be proposed, for the drainage of the metropolis. And here we deem it right, as well as expedient, to state that we lay no claims to the possession of engineering knowledge. If, therefore, we are not in a position to offer an opinion calculated to have weight with the practical men who form the present Metropolitan Commission of Sewers, we are at least free from the predilections and personal feelings from which an engineer would find it so difficult to divest himself. Au reste we may, without undue presumption, claim to know as much of the subject in hand as will entitle our observations to a moderate share of attention.

In utter ignorance of the plans which may have been sent in to the Commission, but with some knowledge of the projects put forward while the old Commission was in existence, we would venture to point out three obvious ways in which the drainage of the metropolis might be effected:

1. The existing sewers and watercourses, with their existing outlets, may be retained, subject to repairs, improvements, diversions, extension of outlets into the bed of the river, embankments, and the aid, where necessary, of the steam-engine to raise the water into the river at high tide, new main-sewers being built if required, and new districts being drained either into them or into existing channels. 2. Two large tunnelled sewers may be constructed parallel with the banks of the Thames, one on each side, extending for several miles down the river, their waters collected in appropriate reservoirs, and raised and pumped into the Thames. 3. Each small district of the city having been surveyed, may be drained de novo into a covered reservoir situate at the lowest point of that district;

the heavier solid matters brought down by the sewers having deposited themselves in these covered reservoirs, an overflow-pipe may be made to convey the sewage to a receptacle common to several such reservoirs ; over which receptacle a steam-engine may be erected, furnished with a lift or force-pump as occasion may require, so that the liquid may be discharged either into the nearest existing sewer or water-course, or forced forward direct into the Thames.

We will consider each of these plans, in relation, first, to the drainage of London, and then to the profitable application of the manure to agricultural purposes.

1. The first plan, which may be designated as an improved status quo, certainly possesses the advantage of economy. Making every allowance for repairs of existing channels, small and large, for reconstruction of such as are hopelessly faulty, for reservoirs (should such be deemed essential) at the water's edge, and for steamengines as mechanical aids, there can be little doubt that this plan would be an economical one.

2. The second plan, viewed in the same light as a plan for drainage, substitutes two tunnels of great length, and necessarily at great cost, with large reservoirs and powerful steam-engines, for the less expensive works required by the first-named plan. It is therefore open to the great prima-facie objection, that it could only be carried into effect by a large outlay of money. In spite of its great simplicity, we are not surprised to find it summarily condemned by Sir John Burgoyne.

3. The third plan, which may be styled the plan of drainage by districts, viewed still in the same partial light as the foregoing, appears to us to present certain advantages, among which economy certainly finds a place. When compared with the first plan it obviously possesses the advantage of incurring a minimum cost for drainage, by superseding the necessity of branch-sewers continually increasing in size till they approach the dimensions of the main-sewers. It has the additional recommendation

of intercepting, at short intervals, the heavier solid matters, which, under our present system, accumulate in immense masses in every faulty part of our existing channels, necessitating the costly alternative of hand-labour with its risks of suffocation, or flushing with its dangers of inundation. Under this plan, too, the huge elongated cesspool, which by a vast labyrinth of house-drains binds every tenement in a vast district into one gigantic system of foulness, dwindles into comparatively small dimensions.

Whether the economy effected by the substitution of comparatively small main - sewers for the larger channels required where the drainage area is of greater extent, is such as to meet the excess of expense of a number of small steam-engines over the cost of a few of larger dimensions, is a question which must be left in the hands of practical men. Should this question be answered in the affirmative, we own to a very decided preference of this system of drainage over every other.

We have now to consider the three systems of drainage in relation to the application of the sewage as manure.

1. Viewed in this light the first system, or improved status quo, puts forth but slender claims to acceptance. As all the sewage is supposed to flow to the existing outlets on the banks of the Thames, from those outlets, by steam-engines erected over or near them, and by iron pipes laid through the streets, the sewage must be pumped back into the country. If, however, we suppose any of the plans recommended for obtaining a solid manure by chemical precipitation of the less valuable constituents of the sewage to be adopted, then the position of the works on the banks of the river would certainly possess the advantage of cheap water-carriage.

2. The second plan of a doubletunnelled sewer is even less advantageous in relation to the profitable application of the sewage than the one we have just considered; for as it conveys the sewage to two reservoirs situate at distant points low down the river, it virtually limits the use of the sewage to the land lying within a radius of a few miles from those points. If it should be deemed expedient to apply a portion of the immense quantity of sewage

there accumulated to lands situate on the borders of the metropolis higher up the stream, the pipes would have to be laid down at immense expense to the very districts from which the sewage had originally flowed. Instead of mains of moderate dimensions radiating from the several existing outlets to the lands lying nearest to such outlets, we should have mains of large size describing a retrograde course of several miles in length, from the fardistant reservoir in the marshes of Essex or the meadows of Kent. Even if provision were made for drawing sewage from any point of the tunnelled sewer, as was suggested many years ago for the town of Glasgow by the spirited and ingenious author of the Harleian dairy system, and more recently for Manchester by Mr. P. H. Holland, the same objections would still apply as to the system just examined, with the additional one of the expense incurred by raising the sewage from so great a depth.

3. If the system of drainage by districts presented some advantages over its competitors, when considered simply as a mode of ridding the metropolis of its foul waters, it certainly stands forward in very bold relief when viewed in the light of which we are now speaking. Though, if that system were carried out to its full extent, the districts immediately bordering on the Thames might still, as at present, be most conveniently drained into the river; a considerable proportion of the outlying districts might be drained outwards towards the country, so as to present convenient centres either for restoring the sewage to existing channels, or for distributing it through iron pipes over the adjacent lands. In our eyes, this is a great and peculiar advantage which the system of district drainage enjoys over its rivals. It offers at many different points on every side of the metropolis its temptations to the owners and cultivators of the soil. Nor must we forget one peculiar advantage pertaining to this system, namely, that it alone professes to separate the house-drainage from the surface-drainage, so as to collect the manure free from silt on the one hand, and of a strength to pay even for cartage to a moderate distance on

the other. To make the system perfect, however, the reservoirs ought to be so situate that the engines may have the command both of unmixed house-drainage as manure for winter use, and of the means of dilution to fit it for irrigation in the summer.

It will be seen, then, that of the three systems of drainage to which we have adverted we give a decided preference to the third. We think it likely to be the least expensive in the long run; and we contend that it offers the best prospect of an economical and profitable application of the sewage to the purposes of agriculture. At any rate, we submit that it is one that ought to be adopted in the case of all the outlying districts of the metropolis within the jurisdiction of the Metropolitan Commission of Sewers.

On the subject of the application of the sewage of London to agricultural uses we must be allowed to add a few words. It is evident to our mind that some years must still elapse before this valuable fertilizer will meet with general acceptance at the hands of the cultivators of the soil, and many more years before the commercial public will be induced to invest capital in schemes for its distribution. Though the efforts of the enterprising company which is at work in Fulham fields, conferring on the market-gardeners of that district the great advantage of a supply of dilute sewage, with unrivalled facilities for its application to the soil, have been crowned with a fair measure of success among the smaller holders of land, the more opulent cultivators still hold aloof, and still cling with dogged obstinacy to the old methods of culture. On the course which they may see fit to adopt the question of the commercial value of the sewage of the metropolis mainly depends. The failure of the present attempt, which must speedily follow on the prolonged refusal of the larger cultivators to cooperate with the company, would effectually deter other parties, whether in London or in the provinces, from embarking their capital in similar projects. On the other hand, the success of this first venture would be the signal for the commencement of hundreds of similar schemes in every part of the country.

Such, then, is the present position of one of the most vital questions of our time-the question whether the great inherent value of sewage manure can be converted into an equivalent commercial value-the question whether it will pay to distribute this material as a fertilizing water. If it will not pay in this form, we feel confident that it can pay in no other shape. The dilute state of the liquid, which peculiarly fits it to serve both as manure and as water, offers an insuperable obstacle to the obtaining from it by precipitation the more valuable of its constituents; and there is great reason to fear that the best deposit which can be obtained from it will not be able to compete with existing manures at a price to cover the cost of its preparation. We should be but too happy to find that we are mistaken in this view of the subject; and in order to multiply the means of proving ourselves in error we would strenuously advocate the adoption of such a plan of drainage as shall give the greatest facilities for experiment in the fabrication of manures, and the largest opportunities for the trial of their virtues. Now it must be obvious to the meanest capacity that the plan which combines these two desiderata is one which multiplies places of collection or deposit in or near agricultural districts, and at the same time separates house-drainage from upland and surface waters. If, contrary to our expectation, a profitable solid manure be obtainable from sewer-water, it must be by acting on the strong sewage as it flows from our houses; and if this is to have a ready sale it must be in or near the centres of its production.

These preliminary considerations I will enable us to set forth in few words the particulars of the system of drainage which we are disposed to advocate. Its essential parts are the following:-1. The division of the entire area of the metropolis into districts of such moderate extent that the size of the largest drains shall not exceed that of the largest earthenware tubes manufactured for that purpose. 2. The convergence of these drains in a covered cesspool or cesspools, so arranged as to admit of the prompt removal of all solid deposits. 3. The further convergence

of several of these small districts by means of overflow-drains in a covered centre, over which a steam-engine shall be erected, by means of which the sewage may either be raised or propelled into some existing sewer or water-course, or be placed in either of these ways at the disposal of the agriculturist. 4. The complete separation of house-drainage from the surface and upland waters, with a view not merely of securing a strong sewage for distribution or precipitation, but also of excluding the silt of the streets, which forms in the existing sewers the material of the most troublesome deposits. 5. The efficient repair of existing mainsewers and water-courses, and such a command of water as shall ensure a uniform and steady flow of sewage through them at all times of the day. 6. Such an alteration of the outfalls of existing sewers as shall prevent the sewage from flowing over the banks of the river, and cause it to be discharged at once into a sufficient body of water to destroy all offensive

odour.

With regard to the appropriation of the sewage to agricultural uses we have these additional suggestions to make-1. That the cesspools which connect the overflow-pipes of the several smaller districts should be placed near an available supply of water, so that if there should arise a demand for the sewage it may be diluted to the necessary extent during the summer months. 2. That, in the first instance, the steam-engines should be furnished with lift-pumps, so that the sewage might either be discharged into existing sewers or water-courses, or placed without charge at the disposal of any one who might desire to make use of it, with the single proviso that it shall be drawn at hours and into receptacles approved by the Commissioners of Sewers. 3. That should a number of proprietors of land or a commercial company desire to lay down pipes for the distribution of the liquid, they should be permitted to substitute a force-pump for a lift-pump, and enjoy the use of the sewage free from charge for a short term of years.

If such facilities as these were given, we are of opinion that a very few years' experience of the value of

sewage manure would serve to create a demand for it, which might justify the Commissioners in levying a royalty upon all parties making use of it. It is not at all improbable, moreover, that through these facilities thus freely offered the great problem of the profitable and inoffensive application of the contents of our sewers would work itself out in a manner to obviate every conceivable objection to its use. Having obtained command of house-drainage free from the admixture of silt, and containing little besides animal and vegetable matter, a solid manure might be thrown down by milk of lime or other chemical means, which if sold in the moist state in the immediate neighbourhood would pay the cost of production, while the supernatant liquid, free from odour and colour, but still containing a valuable manure, might be either pumped out into the rural districts or returned into the Thames.

Once more we repeat that we fully agree with Sir J. Burgoyne in thinking that the first duty of the Commissioners of Sewers is to drain the metropolis efficiently and cheaply, and that the application of the refuse to the purposes of agriculture ought to be a secondary consideration. At the same time the Commissioners ought not to suffer themselves to be misled by the simplicity and grandeur of any scheme proposed for their acceptance, so as to overlook the obvious advantages of the separation of house-drainage from the upland and surface waters, the multiplication of the points at which the sewage may be offered as manure to the agriculturist, and the prospect (we trust not a very remote one) of applying the valuable refuse of London to its proper use, with the greatest advantage to agriculture and some contingent profit to the Commission itself.

Before we conclude, one word with the Government. We are not of the number of those who would constitute the authorities in Downing Street the Hercyles to lift every waggon out of the rut; but we would make the Government, as the centre of enlightenment as well as of authority, the means of advancing great public objects by which its own pecuniary interests can be promoted. We look upon the Woods and Forests