sewage extending over 45 acres in a course of 20 miles, and would be liable, in winter, to be frozen or choked up with snow.

Before a system of fluid manuring be adopted in the county of Essex, it behoves the authorities generally to consider whether the effluvia from an extensive area, saturated with stale sewage, poisoning the atmosphere by putrifying and steaming during the heat of summer, might not be as injurious to the health of Kent and Essex-aye, and of the metropolis itself, as the most efficient subterranean removal of sewage could be beneficial to the health of London and Middlesex.

Now let me turn, in contrast, to the deodorising system :

of tons of sewage, discharging only pure water into the river Soar, which the mass of separated impurity would otherwise have contaminated.

The sewage is conveyed to a spot less than a mile distant from the town of Leicester, and there, as rapidly as it arrives, and scarcely allowing time even for incipient putrefaction, it is raised eighteen feet, by pumps worked by steam power. Whilst passing from the pumps the sewage becomes intimately mixed with a body of lime and water, proportioned to, and constantly varying with, the nature of the sewage, which produces an instantaneous and perfect deodorisation. It then flows successively through two canals; the first 60 and the other 130 feet long, 45 feet broad, and 16 deep, which are traversed by the sewage water in about two hours and a-half, and the portioned is almost pure, and perfectly scentless, whilst the greater portion, or about seven-eighths of the solid matter originally held in solution or suspension, is deposited as fine mud in a trench at the bottom of the first canal, from which, by an Archimedes, or endless screw, the fresh deposit is moved by a continued action from beneath the deep stratum of the deodorised water, into a covered well. Thence it is lifted through a brick shaft to a small tank, in the upper part of the building, by a Jacob's ladder, similar in principle to the ladder of buckets used in dredging machines. A series of centrifugal machines are then charged with it, and effect the separation of the remaining water, leaving the deposit in a plastic state, fit to be formed into a brick or cake for drying. At present nearly 3,000 tons of this half-dry deposit are heaped up in the yard of the Leicester works, and emit no smell whatever.

Here is a bottle of the stygian stream flowing day and night through the deep sewers of Leicester, 18 feet below the level of the ground. In the act of being pumped up from the sewer, it is mixed with the substance contained in this bottle (the cream of lime) in proportions varying from 2 to 16 grains to a gallon, which instantly deodorises it, and gives the mixture the appearance you observe in this bottle. A rapid separation takes place, and the limpid effluent water, of which this is a sample, flows into the river, and leaves behind it a deposit which, upon being dried, is converted into this inodorous powder.

Before proceeding to describe, by the aid of drawings and models, the process, arranged and perfected by Mr. Wicksteed, at Leicester (to whom we are indebted for conceiving and working out the system), I will give in a few words the early history of the undertaking.

As far back as 1845, Mr. Thomas Wicksteed, formerly engineer to the East London Waterworks, a name well and honourably known in connexion with questions of water-supply and sewerage, was called upon to examine whether there might not be some practical and profitable mode of dealing with the sewage of London, and brought forward, at the suggestion of the late Professor Aikin, a scheme for separating, by means of lime, the solid matters and salts contained in sewage water. so as to render them portable and to apply them to fertilizing the soil, whilst the effluent water was discharged, free from all impurity. Continuing to bestow for several years much attention to this subject, he introduced various practical improvements, which elicited a very favourable opinion from Mr. Robert Stephenson, corroborated by Professors Aikin and Taylor. A few gentlemen interested in the general question of the improvement of the salubrity of towns, subscribed £2,500 to try its efficiency by an experiment on a large scale at Leicester.

The result proved eminently successful; an act of incorporation was, consequently, obtained, and an engagement entered into with the authorities of Leicester, a town of 65,000 inhabitants, and full of manufactories, to purify its whole sewage, for which Mr. Wicksteed had also originated a plan of artificial drainage. This lastmentioned improvement was nearly completed in May, 1855, and the deodorizing works, which after numerous preliminary essays had been simultaneously executed, were then brought into full operation. Since that period the works have been in constant operation day and night, and in the course of nineteen months have separated about 6,000 tons of solid matter, from seven-and-a-half millions

For the interior of towns, where it is desirable that the operation should be closed in, a new patent filter, manufacturing about two tons of solid matter at one operation, is preferable to the centrifugal machines. The filter system admits of no communication whatever with the atmosphere, at any stage of the operation, until the deposit is withdrawn from it in the form of flat firm slabs, forty inches square and three inches thick, to be dropped from the press into a barge for daily removal. A full-sized filter would manufacture about eight tons daily, and three men and a boy could manage twenty to twenty-four filters. The following results are thus easily attained.

1st. The solid matter and salts held in suspension and solution in fresh sewage water, can be deposited by the chemical and mechanical action of lime before putrefaction commences, and can be manipulated in closed works and without exposure to the outer air, up to the moment of their conversion into firm inoffensive slabs, well suited for removal; a boat or cart-load of which, would be quite as unobjectionable as one of unburnt tiles or bricks.

2nd. The deodorized water, after passing through the first short canal of sixty feet in length, which may be viewed in the light of an enlarged continuation of the sewer itself, is so free from solid matter that it might be employed for flushing or diluting a lower line of sewers. To fit the deodorized water for street watering or for being discharged into an open river as at Leicester, it must be passed through a second canal from 130 to 250 feet in length, according to the degree of transparency desired. It must be borne in mind that after being thoroughly mixed with the lime the water is without smell, and therefore no longer requires to be vaulted over, but may be exposed to the atmosphere in an open channel where desirable.

In speaking of these channels, whether built-in or open, I have employed the term "canal," with the view of disassociating them from the idea of stagnant cesspools. There is no analogy whatever between them and the cesspool-reservoirs or vast vaults of deposit to be formed on the banks of the Thames. It can hardly be doubted that the frequent necessity for cleaning out a pestilential accumulation of semi-liquid sewage from these last, would

day enter as a component part into the vegetable system. Nothing therein would be wasted by nature, though so recklessly disregarded by man; useless, indeed, worse than useless to him, till vegetation has, by its re-constructive power, again organised, in the growth of its own structure (the future food of a higher order in creation), that very refuse, which animal life, having previously derived from the same vegetable source, had afterwards rejected as useless or effete.

The vegetable kingdom, placed by the Creator in the beginning, on the confines of vital existence, as the inanimate purveyor for animate life, is the true Phoenix, which springs a-fresh with ever-renewed vigour from the ashes of decay.

course to the river would have to be conveyed through such an extent of the comparatively level county of Essex as could consume the water for irrigation.

Supposing the season to be favourable for irrigation, and the whole of the water to be required at any particular time by the farmers, the sewage would be treated with a greatly reduced charge of lime, only just sufficient to fix the sulphur, and precipitate the coarser and more putrifiable matters in suspension, allowing the salts in solution to pass off with the still turbid but deodorized water in such a state that the whole would sink into the soil without leaving a putrifying scum on the surface.

When a reduced quantity of irrigating water was needed, it would be passed down during a sufficient number of hours only to meet the demand, and at those hours when experience would have shown that the fertilising salts were most abundant in the sewage.

to the mansion of the rich.

The magic words that shall bring about this magical result are

IRRIGATION AND DEODORIZATION. Deodorisation, in its practical sense, does not simply mean the removal of offensive smell, but the purification of the water by the abstraction of all extraneous matter, 800 or 1,200 tons of water only furnishing one ton of solid dry residuum.

If this deposit is to be utilised, it must contain the salts, and especially the ammoniacal salts, with the undecomposed nitrogenous matter, but if the fluid part is to be employed for irrigation, then the suspended matters alone should be separated, leaving the more valuable salts in solution.

We now arrive at the question, what is the cost of production of this heterogeneous compound? I will give the answer for a population of 500,000.

Buildings and machinery, consisting of the lime pits, reservoirs, Jacob's ladders, and filters, £40,000, at £4 per cent.

6 lime men, at 20s. per week... £6

15 filter men

6 lads at 10s.

2 reservoir men at 20s.

Per Annum.

£1,600

1,352 473 3,250

325

Total......... £7,000

The make of deposit from the filters will be 60,000 tons per annum in a plastic state, like clay ready for brickmaking, the cost being 2s. 4d. per ton, including the discharge into carts or barges lying alongside the works. The cost of removal I have not thought it necessary to include, as it may be set against the clearing out of the proposed reservoirs on the Thames.

Such an arrangement might be facilitated by a simple London works. By this combined system none of the sewage would ever run to waste, infect the atmosphere, or pollute the Thames at any part of its course. I shall presently have occasion to allude to a recommendation of the engineer of the Board of Works for the establishment of a deodorizing station near Kensington for the Middlesex sewage. Should that recommendation be hereafter adopted it is obvious that the land owners in the western district would enjoy every facility for enriching their own land by irrigation with their own sewage, instead of absurdly sending the sewage on a long journey through the metropolis to the Essex farmers at a cost of £12,000 per annum. The proposed system of metropolitan drainage does not provide for the sewage of Isleworth, Brentford, or Acton, which will continue to pollute the river above the bridges. The cure for the evil is obvious, namely, local deodorizing works at Brentford.

Before I attempt to explain the treatment to which I would suggest that the metropolitan sewage should be subjected, I will give a brief sketch of the new drainage plans for the metropolis, and the present state of that vexed question as it now fluctuates between the Metropolitan Board, and the chief Commissioner of her Majesty's Board of Works. And first, let me call your attention to the more serious evils of the present state of the sewerage of London. The Thames has ever been the grand arterial sewer of London; into it the drains of the whole metropolis flow at numerous places and at various levels. On either side of the river there is a considerable extent of low land, and the houses closely built upon it have their basements so much below the level of high water that the sewers beneath them can only discharge their contents for about four hours in every twelve, when the tide is lowest. The sewers are closed at their outlets during the rest of the day, by floodgates which prevent the river water flowing up and submerging the cellars of the houses, and are thus converted into cesspools under the streets, in direct communication with the houses built over them, where the sewage accumulates, stagnates, and putrifies.

Sewage, so detained in its passage to an outfall, becomes far more offensive than that which can flow off uninterruptedly, and any new system should obviate entirely this serious objection to the present mode of draining.

To effect the double object, the effluent stream on its

of the tide. But this has not been done; the sewage is merely conducted to some near drain in the low district and subjected to the same inconvenience of being tidelocked, adding to the fetid mass for sixteen hours in the twenty-four.

But this is not all. The rain water which falls upon

all the districts, both high and low, also descends into the low sewers, and as these are not of sufficient capacity to store the sudden influx of storm-water, in addition to the sewage already stagnating in them, whenever a heavy storm occurs they become overcharged, and in such cases the putrid sewage floods and destroys much valuable property, leaving entire streets unhealthy and damp for many days after.

Such is the present state of our London drainage and its main objections.

The cure of the evil is to be accomplished

I. By an unintermitting flow in the sewers of those parts of London whose subsoil is below the level of high water, and this can only be effected by pumping up the contents of the drains to a level above high tide, in order to overcome, artificially, the natural disadvantages of these low districts. This is technically called providing the drainage with an artificial outfall, a mode of overcoming the difficulty of draining a flat district, first proposed by Mr. Wicksteed, for the city of Berlin, in 1841, and tantamount as described by Sir William Cubitt and Mr. Stephenson, in their report on the 17th of October, 1853, to raising the level of this low district twenty feet, and entirely overcoming the natural disadvantages of its

situation.

II. The sewage of the upper districts must be intercepted and conducted to a natural outfall by gravitation before putrefaction commences.

III. The sewage conduits must have no communication with the houses or the outer air; the discharge must not prove a focus of infection and pestilence, and the Thames must no longer be a cesspool for the sewers of London. At present, with each rise and fall of the tide, the accumulated contamination of more than fifty days oscillates up and down the stream between Gravesend and Richmond.

The outfall of the sewage is, therefore, the pivot point of the entire system to which the local drainage is subsidiary. On this all-important point Mr. Stephenson and Sir William Cubitt reported their views, founded upon a series of experiments made by the late Mr. Frank Forster, the main object of which was to determine how near to London the sewage could be discharged into the river, without finding its way back again to the inhabited parts of the town. The experiments proved that it was essential to go at least as far as Barking Creek, and discharge the sewage at or near high water. For the delivery of the sewage into the river at high water is equivalent to its discharge at low water, at a point twelve miles lower down the river; therefore the construction of twelve miles of sewer is saved, by discharging the sewage at high, instead of low water.

I will now point out on this large plan the works proposed for the south side of the Thames. The low level sewer provides for a district of twenty-two square miles. This sewer commences at Putney, and is carried by Wandsworth, Battersea, and Kennington, to the pumping station on a piece of waste land on the east bank of Deptford Creek. The total length of this sewer is nine miles. The high level sewer is designed to intercept the sewage of fourteen square miles by gravitation. It commences at Clapham Common, passing by Brixton, Camberwell, and Peckham, and along the Greenwich road to the Deptford pumping station. Here the sewage of the "low-level sewer" is pumped up twenty and a half feet into it by engines of 520 horse-power. From Deptford Creek the united streams flow by gravitation to Woolwich, and thence through the marshes to Erith Reach.

To contain the sewage till discharged into the centre and bottom of the river, near the time of high water, a covered reservoir of 4 acres is to be constructed, capable of containing 1,000,000 cubic feet of sewage.

We will now pass over to the north side of the Thames. The entire area north of the Thames, from which it is proposed to intercept the sewage, comprises about sixty square miles. For this area it is proposed to construct

four main lines of intercepting sewers, forming four separate drainage areas, viz., the northern high level, and the middle level areas, from which the sewage would be conveyed by gravitation; the low level area, from which the sewage would be pumped into the high level outfall, common to the three areas, and the western area, for which two alternative propositions were laid by Mr. Bazalgette before the Metropolitan Board; the one which he recommended for economy, and as averting serious engineering difficulties, was the employment of deodorizing works near the mouth of the Kensington canal; the other proposition, which he seems to have given reluctantly as a pis-aller, costly and difficult of execution, inconvenient to traffic, and monstrous in its disregard to the health of the most populous part of London, was to carry the sewage of the whole twenty-two square miles of the western district into and through the chief thoroughfares of the cities of Westminster and London, because the deodorization of the sewage was locally objected to.

The northern high level area includes about ten square miles. The sewer commences at the foot of Hampsteadhill, and passing through Holloway, Hackney, and Victoria-park, to the river Lea, over which it is carried by an aqueduct. The middle level area includes about seventeen square miles, commences at Kensal Green, and passes through Notting-hill, Oxford-street, Clerkenwell, and Bethnal Green, and effects a junction with the former sewer, with which it will be carried over the river Lea to a reservoir, and thence discharged into the Thames at high water. The low level area includes about eleven square miles. The levels are so low that the aid of pumping is necessary to produce efficient drainage.

The low level sewer commences in Chelsea, passes along Parliament-street, by Whitehall, to Charing-cross, the Strand, and Fleet-street, to New Bridge-street, where it intercepts the Fleet sewer, Cannon-street, King William-street, thence through Eastcheap, Tower-hill, and Limehouse, passes under the River Lea, to a pumpingstation near the Abbey-mills. There the sewage will be lifted about 37 feet to the high level sewers.

Mr. Bazalgette, in this part of his report, takes an opportunity of reiterating a recommendation which he, in conjunction with Mr. Hayward, had made two years before. He says, that the low level sewer should be constructed as near the Thames as practicable, both to avoid the public inconvenience along crowded streets during construction, and to intercept the sewage close to the existing outlets.

Should the long-contemplated embankment of the Thames between Westminster and London-bridge be carried out, much of the cost and difficulty of a river line of sewer would be obviated, and the intercepting sewer might be most advantageously constructed in conjunction with the embankment between Hungerford and London bridges.

The main difficulties and the greatest inconvenience would occur along the Strand, Fleet-street, and eastwards; and this route involves the necessity for reconstructing and reversing the direction of all the branch sewers on the south of the line.

The ultimate object is the purification of the Thames. That object cannot be obtained until the channel of the river is deepened, its scouring-power increased, and its mud banks removed by the construction of a proper embankment in conjunction with the scheme of interception.

Mr. Bazalgette adds,-I beg to state, that a large amount of risk and capital may be saved, by executing this sewer in conjunction with an embankment along the north bank of the Thames, and that the execution of both these works is essential to the full attainment of the object desired.

This is not the opinion of the metropolitan engineer alone, but of many of the most experienced engineers in the country; yet this urgent recommendation is passed by, and the fetid mud-banks of the Thames are likely to continue a disgrace-unparalleled by any city on the Con