Part 58
Proprietors of large spaces of ground, or a combination of small ones, might also claim and be authorized to form and execute their own plans, provided always that they were previously submitted to examination and approval by properly constituted authorities.
It has been omitted to mention, that towns built on a regular plan, and upon sanitary and commodious principles, are much less liable to the accidents of fire, and the consequent loss of life and property; and when such do occur, the facility of extinguishing them is much greater; and one might also venture to predict that it will be found that the new town of Edinburgh has suffered less from fire than any other town in Great Britain.
Prevention against fire is a subject well meriting consideration when treating of the improvement of towns. It would seem that fires more particularly occur in large public and private buildings, as for instance, the Albion Mills, the theatres of Drury-lane and Covent-garden, the Houses of Parliament, the Great Armoury in the Tower, Royal Exchange, &c.; and it would be well to provide that all such buildings should be detached, as well as manufactories and all buildings containing steam-engines: but previous to legislating on the subject it would be desirable to collect the statistics of conflagration, which might readily be obtained from the fire-insurance offices.
_Ventilation._—In new towns, or the increments of old towns, good ventilation will be best secured by attending to the principles laid down for the construction of such.
The noxious ingredients which must exist more or less in the atmospheres of all large towns may be dissipated by currents of air, or diluted by access to large open spaces, while the origin of the evil may be much reduced by a good system of sewerage.
For the removal of noxious vapours existing in crowded towns the following points deserve attention:—
1. The conversion of blind alleys into thoroughfares.
2. The continuation of leading streets through blocks of houses on which at present they abut.
3. The opening of wide and straight streets through the meanest, most complex, and crowded parts of cities; this will prove the most important measure for meeting the object in view; and what merits the next consideration is the preservation of such good and healthy avenues as already exist free from encroachments: for it has happened in the metropolis while exertions were making in some districts to open wide streets, in other districts a contrary system was at work. The New and City Roads, the most commodious avenue in the vicinity of London for length, width, useful and healthy communication, is in a constant process of invasion, as may be noted more particularly in the vicinities of Tottenham-court Road and King’s-cross; and unless some measures are taken to preserve this noble respiratory of the metropolis, it is to be feared in a short time its character will be entirely changed.
4. Another mode of improving the air of towns is to open squares, or public walks, or gardens, by the removal of some of the buildings, by which means a reservoir of pure air is created, and in this manner the city of Seville was essentially benefited; the streets are there numerous, narrow, and dirty, but the city, abounding in large convents, the removal of some of them, and the conversion of their ample sites into piazzas or squares, afforded the air and space so much required for the public health.
In London there are some institutions that might be advantageously removed to the suburbs or skirts of the town, such as the Charter-house School and the Fleet Prison, and their sites converted into open squares; but if such operations are too costly and difficult, we may at least guard against the converse operation, viz., the covering of open sites with masses of buildings. Thus we have seen in recent times the gardens of Lincoln’s-inn and Gray’s-inn invaded; and we had lately a proposition to convert Lincoln’s-inn-square into piles of buildings, and to demolish what no art can supply, the finest reservoir of air which the metropolis offers to a crowded neighbourhood.
5. The circulation of pure air would be much increased by pulling down all dead walls, and by substituting iron railings in their stead; and too much credit cannot be given for what has already been effected in this respect in the neighbourhood of Knightsbridge, &c.
6. The prohibition of all burials in the metropolis and other large towns, and the consequent diffusion of unwholesome effluvia.
_Drainage and Sewerage._—As towns become more crowded, the value of good drainage and sewerage as a sanitary measure becomes the more apparent; and as the means of draining the site of a town above and below the surface is to be effected in part by the same means as the sewerage or removal of the liquid filth, the subject becomes of great importance, and second only to the choice of the site of the town and distribution of its streets; and if a _due regard to system_ has been shown to be so desirable in the one case, it is no less so in the other, and before any buildings are commenced the plan of drainage should be matured.
In order to arrive at a good system of drainage for a piece of ground intended to be built upon, or in a town where the sewerage requires improvement, a necessary step in the process would be to add to the plan of the town lines of equal altitudes, drawn at every two or three feet of elevation, which would present at one view the means of comparing the levels over the whole extent of the town; they would show the deepest valleys where the main sewers would most conveniently run, and the most efficient mode of combining the several classes of drains, so that the declivities might be turned to the best account; in addition, the plan should be so far geological as to show the boundaries of the strata, as a body of marl or clay often upholds a quantity of water which might prove injurious as a building site if not previously tapped.
A notorious instance of this nature occurred at the village of Moseley, near Birmingham. Preliminary to carrying the Gloucester Railway through the village, in deep cutting, it had been ascertained by trial shafts that the bottom consisted of quicksand, which rendered it difficult either to construct a tunnel or to support the slopes in open cutting until the water was removed; and for this object a drift or level was brought up from a distance of a quarter of a mile through a bed of marl; the miners proceeded for some distance perfectly dry until they reached the quicksand, when the water flowed into the drift at the rate of 253 cubic feet per hour, or 77½ gallons per minute, and the wells in the village in a short time were laid dry, and had to be deepened at the expense of the Railway company. It so happened in this instance that the level of the quicksand was so deep that the surface of the land had not been affected by the pending up of the water below; but if it had been otherwise, the measure resorted to would have proved as useful to the land as it was to the Railway.
In laying out a plan of drainage and sewerage when a river or brook passes through or alongside of a town, it will naturally become the main drain of the place, and be the normal line from whence the second-class sewers would diverge; but it not unfrequently happens when such a brook is small and becomes the _cloaca maxima_, that, being left open, and insufficiently supplied with water in the summer season, it constitutes, instead of a benefit, a serious nuisance to the inhabitants; instances of this kind may be observed at Edinburgh, Birmingham, Coventry, Camberwell, &c., &c. It also happens at many towns that a stream passing through or by them is dammed up to turn a mill just above or below the town, or even in the middle of it, by which means the current useful to clear away the filth is diverted, the water in the bed of the stream into which sewers are discharged is left stagnant, while the vicinity of the town is rendered wet and unwholesome from the pent up water.
At Birmingham the Rea Brook is dammed up in its course through the town to supply a mill. In the very excellent sanitary report of the town by Dr. Hodgson and other medical gentlemen, it is stated that “the river Rea may be considered the cloaca or main sewer of the town, but that its condition is very bad;” the report also states, “that the stream is sluggish, and the quantity of water which it supplies is not sufficient to dilute and wash away the refuse which it receives in passing through the town, and that in hot weather it is consequently very offensive; and in some situations in these seasons is covered with a thick scum of decomposing matters; and this filthy condition of the river near the railway stations is a subject of constant and merited animadversions, and that it requires especial attention lest it should become a source of disease, &c.”
The _cloaca maxima_ of Birmingham differs from that of ancient Rome; that whereas in the latter art was employed to effect what nature had left undone, here art has been employed to obstruct the useful course of nature. I quite agree with the sanitary report as to the present noxious state of the brook; and even those who travel on the railway may at times be very sensible of the effluvia when crossing it.
I am inclined to differ from the sanitary report as to insufficiency of the water of the Rea for cleansing its own bed; but that report has not adverted to the fact of the abstraction and diversion of the water of the Rea from its natural bed to turn a mill, a fact which will amply account for the deficiency and sluggishness of the current in the very places where the contrary condition is most wanted.
From my inspection of the locality, I am inclined to believe that the descent of the Rea and its quantity of water in passing through the town of Birmingham is sufficient under good arrangements for the efficient and wholesome sewerage of its bed.
If we take a distance of half a mile above the weir and half a mile below it, that is, nearly from Morley-street to Lawley-street, I consider I shall be justified in saying there is a descent of about 14 feet, for I find a slight weir in Floodgate-street; at the dam itself the fall is about eight feet, and from thence for a considerable distance downwards the fall is considerable.
Above the weir the stream for a short distance is sluggish from want of declivity, and the water being pent up, keeps the houses there wet or damp, while below the weir the bed of the Rea being left nearly dry, the filth from the sewers which discharge there must stagnate, while at the same time the water of the Rea passing through the mill-race with a good body and current, applies to no act of cleansing.
The mill-pool is extensive but shallow, and there the filth from above accumulates. When the pool is filled with water it is worked off by the mill, but the gratings prevent dead dogs and such like matter from passing, and are there left to fester at low water.
The remedy is as easy as the evil is great; all obstruction being removed from the course of the brook and the water restored to its original bed, the object would be effected; as to the value of the mill-power which would thus be subverted, it cannot be a matter of much amount in a place where coals and steam-engines are so cheap, and where the constant and regular work of the mill must be an object of some importance.
In applying a remedy to the great evil under notice, the engineer should not be content by merely restoring matters to their original and natural state, but in so populous a town should apply all the aid which art can bestow to assist natural circumstances. The bed of the Rea should be formed with an uniform descent through the town and for some distance below it, by dredging in some places and filling it in others with coarse gravel or broken stones; or, better still, if funds will afford it, by forming an inverted arch of stone or blue bricks to give full effect to the scour of the stream; further, the engineer would render the course of the brook through the town as straight as circumstances would permit by cutting off loops and sinuosities. In this manner, and by reserving the whole body of the water of the Rea for cleansing its own bed, I have no doubt that this main sewer of Birmingham would become as conspicuous for its wholesome and efficient action as it is now for the contrary.
About a mile above the town of Birmingham, there is another mill which I am disposed to think would act rather beneficially than otherwise, in removing the filth from the bed of the brook in its course through the town; for in summer weather when the stream is scanty, by pooling it up and letting the water down with force at intervals, the effect is much increased. Whether the stream of the Rea be so deficient in summer as to require this process, I would not now give a positive opinion, but there are many somewhat analogous cases where the stream in summer is not sufficient and where the pooling up and flushing off at intervals could not but prove of great utility; and if I have now brought the case of Birmingham into considerable detail, it is owing to the circumstance of its exemplifying certain conditions that are common to a great number of towns, and which, in a sanitary point of view, and more especially in regard to the poorer classes of the community, are the most urgent for remedy of any that have fallen under my observation.
In the town of Haddington, a mill-dam crosses the river Tyne in its passage through the place and into the mill-pool; the main sewer is discharged with a diminished and sluggish descent; and on occasion of floods in the river, the water passes up the sewers and occasionally lays the lowest part of the town under water. It would not be difficult to direct the main sewer into the bed of the river below the dam or weir, and by the additional declivity give some current to the water of the sewer, which from the pending up of the river at its present outlet has rendered it almost stagnant, so much so, that in hot weather, and where it is not covered over, the exhalations are very offensive; but was the sewer improved by the alteration mentioned, still the pooling up of the river for the mill keeps the lower part of the town damp, and even subjects it to partial inundations.
One of the medical officers reports, that when “fever has been at any time prevalent in the town, it has been most so in a portion of it called the Nungate,[50] lying close by the river, when during the summer and autumn it is occasionally almost stagnant, and where there is a considerable decomposition of vegetable matter.”
Another medical gentleman, speaking of the main sewer, says, “this small burn is a receptacle of the privies and refuse of vegetable matters from the houses near which it passes; and in those parts where it is uncovered, it forms an excellent index of the weather; previous to rain the smell is intolerable.”
The same gentleman proposes as a remedy that another small burn, having a parallel course at a short distance, should be turned into the sewer to aid the sewerage. From my knowledge of the locality, the recommendation, I should say, is judicious, but in this manner, though the supply of water would be increased, the declivity or rather want of declivity of the sewer would remain the same, and could only be improved by removing the mill-dam, or directing the sewer into the bed of the river below it, as already mentioned. Unquestionably from the pending up of the river, the lower part of the town is at present very ill drained, and it is somewhat remarkable that it was the first site in Scotland visited by the Asiatic cholera.
In reference to the two cases cited and to others of a similar nature, it should be remarked, that the vicinities of the nuisances are chiefly inhabited by the poorer classes, and who from want of influence in their own parts are the more necessarily thrown under the protection of state regulations.
The sewers of a city or town may be conveniently divided into four classes:—First, the main drain or sewer, and this, whether natural or artificial, being fixed, becomes the basis of the system, and upon it the second drains or district class will be directed: these again will receive the third class or street drains; and lastly, the house or fourth class drains, will be discharged into the street drains. In small towns, only the third and fourth class drains will be required; in large towns, three classes of drains may be necessary; and in great cities, all the four classes will be required.
PLAN OF SEWERAGE
With respect to the form of the drains, when bricks are used as building materials, the bottoms of the drains will be best formed of inverted arches of blue bricks, as forming a cheap, hard, and durable surface, and giving every facility from the form, for the scouring force of the water to remove the filth brought into the drain; but whether the curve of the bottom shall be a semicircle or a segment will, I apprehend, depend on the size of the drain. For very small drains a circular form would be the cheapest and best; the next size would be more advantageously constructed of an oval or egg shape, but still of bricks. Drains of a still larger size, viz. the second class, may be conveniently made either of brick or stone, arched and counter-arched at top and bottom with battered sides, either straight or curved; the counter-arches or curved bottoms will conveniently become flatter as the drains increase in capacity to afford greater room for the accumulated water to pass without rising and flooding back into the feeders. The first and second-class sewers must be deep seated to receive their respective tributaries or feeders, with some overfall; and though a sufficient width for large drains may generally be procured, it is difficult in many cases to command enough of depth, another circumstance that can best be obviated by flattening the arches both at top and bottom; but in large drains, where there is a body of water, the scourage will be sufficient, without resorting to deeply curved bottoms.
When bricks abound as a building material, they are particularly convenient for the construction of deep sewers and drains, from the facility of handling in confined spaces; but it is important their quality should be of the best, since if they scale and decay, great expense must be involved in the repair of the drain. The Tipton, or blue brick, is the best for the facework of drains.
In parts of the country where stone abounds, bricks are often little known, and the resources of the district must be made use of; where the blue lias limestone occurs, I have found it a cheap and excellent material for forming culverts and drains of all sizes; and it was used largely for that purpose on the Birmingham and Gloucester Railway.
Annexed is a sketch of the sections of drains varying in form according to their size. The batter which I found most useful and convenient for wall-sided drains was 1 in 9, either curved or straight; the first is the best form in theory, but in small works I found the bricklayers’ and masons’ work more accurately to the straight batter; and the last is, from its simplicity, better adapted to receive any sluices or flush-gates that may be necessary.
Annexed is also a sketch to show the distribution of drains in a town supposed to be built on a regular plan, with a pretty uniform descent towards an axis, which constitutes the site of the main drain; each class of drains consisting of several sizes, it would be most useful as well as economical that the drain of a particular class (if large) should commence with the smaller size, and discharge or terminate with the greater size, a plan that would aid the sewerage of the water.
In a system of drainage, it is necessary to consider that the greater the body of water, or in other words, the class of the drain, the less declivity is sufficient; and the converse, the less the body of water, or class of drain, the greater declivity is required; in the first case, the hydraulic depth compensates for the want of declivity; and in the second case, the declivity compensates for the want of hydraulic depth; the multiplication of these qualities being a function of the velocity or force of the current, due attention to the above is important in economizing or turning to the best account the declivity for the drainage of a large town.
Having arranged the system of sewerage for a town, the next object will be to render it as extensively useful as practice will admit of; and from the experiments and practice of Mr. Roe, the surveyor to the Holborn and Finsbury Commission of Sewers, we are warranted in the belief that a good system of sewerage, aided by a sufficient supply of water, will, in most localities, be sufficient to remove all the dirt which arises in the streets, without the necessity of cartage, and also all the filth of private dwellings which is at present led through drains or pipes, or which by the aid of water may be practised more extensively in future.
We have first to consider the conveyance or discharge of the street dirt into the main sewers, and the discontinuance of the present expense, and annoyance of using carts for that purpose, at least with some few exceptions.
It is pretty obvious, that if the mud of London, like water, could be made to flow through the drains much trouble and expense of cartage would be saved; and it does happen that the street-dirt of London is so diffusible with water, that with a little arrangement such a mode of cleansing maybe followed; indeed it is highly probable that at present more than one-half of the whole mud is carried off by the rains in that manner.
The mud of London, and other great towns in England, may be assumed in wet weather[51] to arise, in three-fourths of its amount, from the grinding or abrasion of the paving-stones, the remaining one-fourth part consisting of soot, shop-sweepings, and cattle dung.
The dirt arising from the detritus of the stones may be obviated in two ways; 1st, by substituting for the green-stone forming the carriage-way, quartz-rock, or quartzose stones. The green-stones contain hornblende and felspar, which grind, like all argillaceous stones, into fine mud or powder mixable in water, whereas quartz rock retains when ground the form of clean sand, neither soiling nor capable of forming mud in itself. The Lickey Hills in Worcestershire are composed of quartz rock, and the roads in their vicinity show its excellence as a material for road making. The quartz rock, however, of the island of Jura is much purer, and that island contains an inexhaustible supply already broken by nature into sizes nearly fit for laying on the roads; and Small’s Bay in the island of Jura would form a convenient loading place, and by means of a jetty and tram-way vessels might be laden at a small expense, and much of the country supplied with the best of all materials for road-making. The substance of the stone is hard and durable, and consequently suffering little by abrasion; and it would be well worth while to try the experiment of Macadamizing one of the leading streets of London with this material, as the means of forming a good road, and at the same avoiding the creating of a great quantity of street dirt.