You are the surveyor to the Holborn and Finsbury Commission of Sewers?—Yes, I am.
By profession you are an engineer?—Yes; I have been engaged as an engineer in the formation of canals and railways, and in the drainage incident to such works.
How long have you acted as surveyor to this branch of sewerage in the metropolis?—Nearly four years.
Have you observed the general state of the sewerage of the metropolis?—I have only seen some of the sewers of other divisions, but I am generally acquainted with the principle of their construction.
Is it generally the same as that in which you found the sewers in the Holborn and Finsbury divisions?—Yes, except that the forms differ in a degree; some are flat-bottomed sewers, others segment-bottomed. For a long time the Holborn and Finsbury divisions have used bottoms of a semicircular form.
The effect of a flat-bottomed sewer, it is to be presumed, when the water is shallow and the flow slow, is to leave a larger quantity of deposit?—Yes; it flows sometimes in a channel, leaving a deposit on each side; sometimes the water flows on one side, leaving a deposit on the other; but in all cases the flat-bottomed sewers occasion a larger amount of deposit with the same flow of water: it is more than one-half difference of the deposit which is left.
What proportion of the sewerage of the metropolis do you believe to be flat-bottomed?—I have not examined the other divisions, but I believe the greater proportion of the sewerage to be flat-bottomed. In the City they have built some of their sewers in a form nearly similar to those adopted in the Holborn and Finsbury divisions; that is, approaching to semicircular. In the Westminster division the invert is a segment of a circle, whose chord being three feet the versed sine is six inches. Most new sewers are making an approach to the better form by having segments.
Is it not the fact that in proportion as the bottom approaches a plane it approaches to the inconvenience of the flat-bottomed sewers, and weakens the force of the current?—Yes, in a degree, it does.
Are there any practical inconveniences, or is there any material increase of expense in building semicircular bottoms?—None; and if the sides are curved also it forms the stronger sewer for the same expense.
How are the sides of the sewers generally built?—As far as I am informed, they are built with upright walls. I know none but the new sewers in the Holborn and Finsbury divisions that are built with curved sides, though I have no doubt that if any new sewers are built under the superintendence of Mr. Walker, who is president of the Engineers’ Society, he would build them with curved sides.
What are the disadvantages of the flat-sided sewers?—They are not calculated to afford the greatest strength. In clayey or slippery ground, where there is a pressure on the sides, they are more easily forced in. I have myself seen instances where expensive sewers have been forced in at the sides. The curved side gives the strength of an arch in resisting such pressure.
Is there any addition of expense in the construction of such forms of sewers as you describe?—Less expense; there is less brick-work required. As compared with some upright sewers with footings, the difference will be two shillings in first size sewers, and four shillings per foot lineal in sewers of the second size, in favour of the curved sewers.
In respect to the levels, how have you found the sewers?—They appear to have been entirely constructed with reference to the locality, to drain to the nearest outlet, and not on an extended view for the whole district, or with any view to sewerage on a large scale. In the Holborn and Finsbury divisions the Commissioners now adopt a series of levels suited from the lowest outlets to the surrounding districts.
Have you heard of any alterations made in the surrounding districts on the same principle?—I have heard of none as adopted generally. The City have lowered several of their outlets; and Mr. Donaldson, on the Westminster, has had the subject under consideration for some time.
What are the chief effects of the piecemeal town drainage without reference to extended levels?—Chiefly that when new lines of houses are built and require new sewers, either the old sewers must be taken up and re-constructed at a great expense, to adjust them to a new and effective sewerage, or the new sewers, if they are adjusted to the old ones, are deficient in fall, and they have greater deposits.
Does the existing form or system of sewerage answer fully and at the least expense the chief objects of sewerage in house and street cleansing, and the removal of noxious substances?—No, it does not, except where the outlets have been lowered, and the sewers continued at a proper level; great accumulations of deposit are occasioned in the sewers, and from their containing the refuse that was at one time deposited in the cesspools, the deposit is more noxious than formerly; the gas is more considerable, it escapes more extensively into streets and into the houses, where the drains are not well trapped. My opinion is that the general health of the men who work and have been accustomed to the sewers, has become still worse; they are more pale and thin, and lower in general health than formerly. The effect of the noxious gases upon men working in these places is to lower the general health. Since I have had the superintendence of the sewers, the men have encountered about half a dozen accidents by explosions of gas.
But is the health of these men who work in the sewers to be taken as a criterion of the health of persons who are not accustomed to such places?—I have had no means of forming a comparison, though I am of opinion that gases which they encounter without any immediate injury would be very injurious to the health of susceptible persons, or of any persons not habituated to it.
The first prejudicial effect of the defective system, then, is to occasion these noxious accumulations; how are they removed?—Formerly, in the Holborn and Finsbury sewers, and at present, I believe, in all other sewers, the streets were opened at a great expense and obstruction (they are so now, I believe, elsewhere); men descend, scoop up the deposit into pails, which are raised by a windlass to the surface, and laid there until the carts come; it is laid there until it is carted away, sometimes for several hours, to the public annoyance and prejudice. The contract price for removal from the old sewers without man-holes was 11s. per cubic yard of slop removed; where they have man-holes it was 6s. 10d. per cubic yard. This practice also involves injury and expense as respects the pavement; a street may be well paved when it is broken up for the cleansing of the sewers, but the portions of pavements so disturbed are never so well put down again; neither can accidents be effectually guarded against.
By what means may these effects be obviated?—In the Holborn and Finsbury divisions I suggested a plan of flushing the sewers, and of carrying off all the refuse by water. This plan has been adopted, and it is now in operation. The breaking up of the streets is avoided by the formation of side entrances; cast-iron flushing gates are fixed in the sewers; the ordinary flow of water in the sewers accumulates at these gates; the gates are opened, and the force of the water is sufficient to sweep off the deposit; and the system may be further extended.
What is the comparative difference in the expense of construction?—The cost of side entrances and flood-gates, as compared with the cost of man-holes, is from 6d. to 1s. less per foot lineal of the length of new sewers.
What other expense is attendant on this improved practice?—The main expense is the attendance of a man to shut and open the flood-gates.
The structural expense being lower, is the ultimate expense of cleansing lower also?—Yes; the expense of cleansing the sewers is about 50 per cent. less than the prevalent mode. Our expense of cleansing the sewers was about 1200l. per annum; we save 600l. of that, and expect to save more; but to this must be added the saving to the public of the cleansing of the private drains, formerly choked by the accumulations in the sewers. This saving, on a moderate calculation, is found to be upwards of 300l. per annum. There is also the diminution of the escapes of gas from the old and continued accumulations.
During what intervals are deposits allowed to remain on the old mode?—The average is in one set of sewers about five years, and in another about ten years.
During which time the public are subjected to all the escapes of gas from the decomposing accumulation?—Exactly so. It could not, however, go on so long but for heavy falls of rain or snow, which occasion partial clearances.
What is the effect of these accumulations upon the private drainage?—That the drains to the private houses are stopped: the first intimation of the foul state of the main sewer arises from complaints of individuals whose drains are affected; the accumulations in the private drains also occasion an expense to the individuals and much annoyance. By flushing the sewers this expense might be, and in the Holborn and Finsbury division it is, avoided.
Might not the price of sewers be reduced even below those you have now in use, the egg-shaped sewers?—With the radiated bricks, I think that the same capacity of sewerage may be secured with less thickness of brick-work. I have given in an estimate of second-class sewers at 10s. 6d. per foot lineal; which is 7s. 6d. per foot less than the common flat-bottomed sewer with footing.
In these main drains a man may go up to examine them. Admitting them to be necessary for the large towns, might not a smaller and less expensive drainage suffice for small towns and villages?—There are situations in courts, alleys, and small streets, where a less expensive form of drainage would suffice. In fact 18–inch drains for short lengths, costing, if made of radiated bricks, 4s. 6d. per foot, would suffice; they would act well in proportion to the goodness of the falls.
Have you found the system of cleansing the large drains by flushing with proper supplies of water equally applicable to small drains?—Yes, equally applicable. A gentleman has tried it on a private drain of 18–inch capacity, and 1200 feet length, and it answers equally well. It is cleansed by the collection of refuse water from 30 or 40 houses.
Might not the drains from private houses be also cleansed in the same mode?—Yes, they might have a small and cheap apparatus for carrying away all ordinary refuse. If in the small drain a brick fell in, it could not be removed by the force of the small quantity of water which could be obtained in such a situation. In our large sewers the heads of water are in some cases strong enough to sweep away loose bricks.
Would it not be of advantage to the occupier, if the private drains were under the same general superintendence?—I conceive it would in management. They are frequently put to great expense by getting persons to attend to them who really do not understand them. They are often now obliged to have recourse to the contractor’s men. Private property is often drained through other private property, and when the drains are choked, if the parties are not on good terms they will not allow each other facilities for cleansing. Under the Finsbury local Act there is a power to enforce the cleansing of private drains, and by way of appeal that power is sometimes resorted to by private individuals.
May we not presume that the same principles of hydraulics, as to the advantages of a flow over a semi circular bottom, are as applicable to small drains as to large ones?—More so from the flow of water being smaller; the greater necessity for keeping it in a body to enable it to carry away the common deposit.
Then there is a proportionate loss in having the private drainage made with flat-bottomed bricks or boards?—Yes, there is proportionate loss from the extra cost of cleansing. Semicircular drains of tiles would be better, and cheaper than brick, for private houses.
Are there any other defects you have, as an engineer, noticed in the prevalent mode of constructing the sewers?—Yes, the prevalent practice is to join sewers at angles, frequently at right angles; this occasions eddies and deposits of sediment that would otherwise pass off with the water; it injures the capacity of the main sewers by obstructing the current of water along them: I ascertained by experiment that the time occupied in the passage of an equal quantity of water, along similar lengths of sewer with equal falls, was—
| Seconds. | |
|---|---|
| Along a straight line | 90 |
| With a true curve | 100 |
| With a turn at right angles | 140 |
The Commissioners of the Holborn and Finsbury divisions agreed to require that the curves in sewers, passing from one street to another, shall be formed with a radius of not less than 20 feet; it is also required that the inclination or fall shall be increased at the junction, in order to preserve an equal capacity for the passage of water, and of effect in sweeping away the deposit.
When by heavy falls of snow or otherwise the refuse of the streets is carried into such sewers, is there any difficulty in sweeping it away?—None whatsoever.
How are the gully-holes or entrances to the drains affected by such deposits?—Under the prevalent system the gullies and shoots are formed so as to retain deposit, on the principle that it is cheaper to get the deposit out of those than out of the sewers. The Commissioners in Holborn and Finsbury, having adopted the flushing principle, have also adopted a new description of gully and shoot, which I proposed to them for the purpose of conveying the whole of the deposit into the sewers; it is then washed away by the flushing.
In what number of years would the saving in cleansing sewers by flushing repay the expense of applying the apparatus to the existing sewers in the Holborn and Finsbury divisions?—In seven years.
What would be the expense of the construction of chimneys to remove the foul air from sewers?—The expense would depend upon the sort and form of chimney that might be used. A suggestion of Mr. Stable, one of the chief clerks of the Holborn and Finsbury commission, appears to meet the case at the least expense. He suggests that the pipes used to carry off the rain-water from the roofs of houses should be connected with the crown of the sewers; thus forming a chimney for carrying off the effluvia from the sewers, and also a conveyance for the rain-water into the sewers. The cost of connecting one such pipe with a sewer would, on an average, be about 3l. 16s. 2d.
Have you any doubt of the practicability of carrying all the surface cleansing of the streets into the sewers, and removing it by conveyance in water, as was proposed at Paris, instead of by hand labour and cartage?—I entertain no doubt whatever that it might be done, where there is a good sewer and proper gully-holes and shoots; with a good supply of water these would carry away rapidly all the surface refuse; the experience of the sewerage in the Holborn and Finsbury divisions prove it.
How does it prove it?—At every opportunity the street-sweepers sweep all they can into the gully-holes, and it is swept away without inconvenience.
One practical witness states that the expense of the cartage alone of the refuse from a Macadamised street of half a mile, in the winter time in the metropolis, is 5l. weekly. What would be the comparative expense of carrying it away by the sewers?—It would save the whole expense of the cartage; it would be less than the present expense of sweeping and filling into the carts, and if there were a sufficient supply of water on the surface, the work might be conducted with great rapidity.
You are aware that one inconvenience of the existing mode of street cleansing, independently of the great expense, is the length of time during which the wet refuse remains to the public annoyance on the surface, until removed by the slow process of sweeping and cartage?—Yes; and the men would appear to delay for the purpose of the dirt being removed, by being washed by rain into the sewers.
Do you conceive that all the business of street cleansing and house draining might be consolidated advantageously to the public?—Yes, clearly so, and with great economy.
Have you, as an engineer, had experience in road construction?—Yes, I have, having taken the levels and surveys preparatory to an Act of Parliament being obtained for lowering the Long Compton Hills in Warwickshire; I afterwards constructed the new line of road on Mr. Telford’s principle.
Considering the drainage of a new district: the under-drainage of the roads and houses and the surface cleansing, would not the public gain by putting the drainage, the road-construction, repair and maintenance of the roads, under the same management?—Yes, the public would get it done much better by one surveyor and one Board than by two. In the old districts, besides the double expense of officers, inconveniences arise from the want of unity between the contractors for the paving and the contractors for the drainage; there is always conflicting interests between the two, and the work is not in many cases done with the economy and expedition which would be practicable.
If the public, who may be ignorant of the science of sewerage and of what it may accomplish, make no complaints, and do not agitate for the adoption of any improved system, in how long a time do you think the improvements demonstrated in the Holborn and Finsbury divisions would reach the other end of the metropolis by the force of imitation and voluntary adoption?—From the apathy shown and prejudice against anything new, however valuable it may be as an improvement, and the various interests affected, such as the contractors for cleansing, I do not expect that they would become general in the metropolis during my life-time. The public are passive, and the adverse interests are active.
You know the description of persons engaged as surveyors of various descriptions in the rural districts and in the smaller towns?—Yes, I do.
Unless care be taken, is it to be apprehended that any new expenditure will be made on imperfect and unwholesome drains with flat bottoms and on false principles at a disproportionate expense?—Undoubtedly, except they have to act on rule, it will certainly be so throughout the country. The drainage that I have seen in the country districts is worse than in the metropolis.
Have you found the sewerage produce any effect in the drainage of the surrounding land?—Yes, we have found it lower the water in the wells, often at great distances. For instance, in forming a sewer in the City Road we found that it lowered by four feet a well nearly a quarter of a mile distance. The only remedy we could advise to the parties was to lower the well: they did so. We afterwards had occasion to lower the same sewer three feet, when the well was lowered again in proportion; so that the construction of the sewer, in this instance, drained an area of 40 or 50 acres on that side, and perhaps further. The water is sometimes in such quantities and so strong in the land springs as to require openings to be left in the side of the sewer for its passage.
Are there any fees taken in the Holborn and Finsbury divisions?—None.
Do you think the system of the payment of officers by fees objectionable?—Yes, highly so.
“Have you met with instances where the drains have not acted, owing to the inadequacy of the supplies of water?—I have not had my attention called particularly to any private drain, so as to notice whether it did not act owing to an inadequate supply of water, but taking the question on the broad principle of the effect of a sufficient supply of water to drains or sewers as beneficial in keeping them free from deposit, I beg to state that I have noticed the effect on sewers of the same form and having the same fall or inclination, and I have found that where there has been an adequate supply of water no deposit has remained in them, whereas where the supply of water was inadequate, deposit has accumulated so much as to render cleansing necessary in a few years: the effect must be the same in private drains.”
[Figure 1 is a representation of the form of the common sewers built in the Westminster division. It is a transverse section, representing, on a scale of a quarter of an inch to a foot, a sewer of the larger sort, the greatest height being five feet six inches and the width three feet. The smaller sewers are made of the same form, but only five feet high and two feet six inches wide. It chiefly differs from the more common form of sewers in not having a perfectly flat bottom.
Fig. 1.
The following figures, 1, 2, are representations of the sewers in the Holborn and Finsbury division of the metropolis, on the same scale as the above. The part in which the joints are marked in the cut is, according to the directions, to be worked in blocks with cement.
Fig. 1.
Fig. 2.
The sides of these sewers form the curves of large radii struck from the centres on the lines a a, the radius for the larger size being about 13 feet, and that for the smaller size in proportion.
The spaciousness of the sewerage in the Westminster division of the metropolis has been an object of pride; and it is stated that the commissioners have walked in procession down one main sewer prepared for the purpose. It was the glory of Rome that some of its cloacæ were so large that boats and chariots might pass through them. All this, however, appears to have been mistaken in principle, and in ignorance of the mischiefs of the generation of gases and of the principles of hydraulics, and their application for the attainment of the objects in question. Mr. Smith, of Deanston, who has introduced the greatest improvements in land drainage, advances the general principle, that the size of sewers should be so adjusted as to have them always as full as possible, with a quick flow; and he contends that the drainage of a city might and should be so constructed as to give rise to as little occasion for men to go through the main drains as there is for men to go through the main pipes for conveying supplies of water. He would make the drains narrow. “Their transverse section should exhibit an oval or egg-shape, having the vertical diameter at least double the length of the horizontal. The bricks used should be made on purpose, with radiating sides.” “Care should be taken to make the building water-tight and air-tight, and to prevent the foul water and effluvia passing into the contiguous soil. Where land drainage is to be received, special openings can be made at intervals to receive it. All private drainage should pass into the sewers under ground by well-secured channels or pipes. Strong clay pipes, of an oval section, hard burned, and with a good arrangement for secure jointing, might be cheaply procured for the purpose.” It may be said that there is scarcely any drainage, even in the opulent districts, that at present meets these conditions. E. C.]
What are the practical difficulties you find in the way of the cheap cleansing of the streets and houses of the metropolis?—The great difficulty of the cleansing of the metropolis arises from the want of proper receptacles for the filth. There is no filth in the metropolis that now, as a general rule, will pay the expense of collection and removal by cart, except the ashes from the houses and the soap lees from the soap-boilers; and some of the night-soil from the east end of the town, where there happen to be in the immediate vicinity some market-gardens, where it can be used at once, without distant or expensive cartage. The charge for removing night-soil from the poorest tenements may be about 1l. per tenement. One house with another, the expense may be said to be in London about 10s. per year, as the cesspools may be emptied once in two years. One house with another they will not produce more than a load of refuse from the cesspools, which, not being composed, there is great absorption of the liquid refuse. I have given away thousands of loads of night-soil; as we have no means of disposing of it, we know not what to do with it.
What is the distance from the metropolis at which refuse is used?—The expense of cartage of course increases with the distance. The average extent of use of it as deposit does not exceed three miles from the Post-office district in the city of London. Some night-soil has been dried, packed up in the returned sugar hogsheads, and sent to the West Indies for use as manure.
Is it not conveyed away from London by canal?—We do not at present, but it might be. There is a penalty in the local Act of 5l., for depositing it on the wharf.
Cannot you convey such manure by railway?—No, there is no mode of conveyance provided. The charge, I believe, is a halfpenny per mile, but that is for the use of the rails only; and the company do not favour the transit of manure, and the farmer or contractor who would convey it must provide engines for himself, which again would not pay. Night soil has not yet been used systematically, and there are no places provided for its reception.
Might not the refuse be disposed of to better advantage than it now is?—The refuse of a great portion of the metropolis might be disposed of to immense advantage, but it must be by operations on a scale beyond the power of private capitalists. The sweepings of the paved streets is good as manure: on grassland it is nearly equal to horse-dung; but it contains so much seed that it scarcely does on ploughed land for immediate use. It produces great quantities of herbage; every year, however, it improves, because the weed is lost from it and the manure is left. When the streets are dry, and it will pay for transit, we sell a few loads. The sweepings from the Macadamized roads consist so much of granite that it is of very little use indeed; and in general the street-sweepings are mixed up with other manure for sale.
You have been engaged in the cleansing of the metropolis, have you not?—Yes; I have been engaged, and my father before me, in the general cartage of materials, and also in extensive business as a nightman, but I have now retired from business.
What is the usual expense of emptying cesspools?—The full price to respectable private houses is 15s. per load, but the contract price is about 10s. per load. The period of emptying is dependent on whether there is any drainage from the cesspool, or whether there are any land-springs. Some would require to be emptied twice or three times a-year, whilst others would go two or three years without being filled. About 1l. per annum per tenement would perhaps be the expense one with another.
Where the cesspools are relieved, is not the ground about saturated?—Yes, it is; in digging the foundations of old houses for new buildings, the earth is found to be saturated. We have frequently to empty one person’s place because it is found that the soil has penetrated through to the neighbours’ houses.
Does not this moisture affect the condition of the house?—Yes, and it would be good economy for the sake of the house, and keeping a dry foundation, to have water-closets and good drainage from the house to the sewers.
By having the water-closets, the expense of the removal of the soil, annually or otherwise, would be saved?—Yes; and the expense of the dearest water-closets bears no proportion to the annual expense of cleansing, though water-closets I think might be constructed at a less expense, on a more simple plan, than they now are. They might be constructed on a principle to receive the rain-water and all the liquid refuse from the houses, which would increase the cleansing.
To effect cleansing on this principle, it will of course be necessary to have the water laid on in the house?—Of course it will. It would greatly assist the cleansing, if the water-companies were required to draw their plugs once at least in the fortnight. It would cleanse their own pipes, and assist in the cleansing of the sewers. The company would say that that would be a great waste of water, but a sufficient body of water might be obtained for the purpose in a quarter of an hour.
Does not the soil bear any value as a manure?—In general it bears no value to the nightman as a manure. One hinderance to any removal to a distance is, that, by the police regulations, cesspools can only be emptied in the night within certain hours. This prevents cartage to any great distance, and cartage is very dear. Some nightmen have paid 6d. per load for the liberty of depositing it. The object of the nightmen is to get rid of the soil early, and return with the cart to complete the emptying in one night. Formerly, before the new police were so much about, the men would empty the cart in any bye street or place where they could; they would, when it was in a liquid state, empty it down the sewers; they do so now when they have an opportunity, and return to complete the job. Formerly the site of the New London University was a place in which the refuse was deposited; so was the site of the new row of grand houses in Hyde Park Gardens. I think the site of Belgrave Square was another place of deposit; but those places being built over, there is now much difficulty in getting rid of the refuse.
What is the expense of cartage in London?—As a contractor, for the use of a cart, a man, and horse a-day, I used to charge 9s. the day for carting stone and rubbish. My successor did it for 7s., but I saw his name yesterday in the Gazette. The cost of the man’s work and the horse will amount to 6s. or 7s. in London.
What distance do your carts in full work travel in London?—A good day’s work to send a load out and return empty would be about ten miles; over hilly parts not so far.
Is the street refuse of the paved streets valuable as manure?—Yes it is; but it is only worth removal when it can be easily carted, that is, when it is in a dry state. The contractor being obliged to cleanse the streets in a given time, it would not pay to have such a number of carts as to complete the cleansing within the time and carry the refuse to a distance. They get rid of the refuse at the nearest place of deposit. In dry weather they have less to do and can turn their carts to account. The refuse is then dry, and it rides well, and may be sold to an advantage, and it sometimes fetches half-a-crown a load.
At what distance from the place of work would it be delivered at that price?—At about three miles distance; not exceeding that.
Is none of the refuse of the metropolis carried further as manure?—Yes; some of the farmers who bring produce to market return with their carts loaded with dung to greater distances.
Is not canal conveyance used?—Much of the street cleansing is taken down the canals.
Do the contractors in general pay for the deposit of the refuse of streets?—They would pay if they could get places of deposit near their work; but all the places out to the outskirts, where any refuse whatever could be deposited, are built upon.
Do not the men sometimes get rid of the surface sweepings into the sewers?—Yes; they do when it is in a liquid state, and when they are not watched.
Do you happen to know what is the expense of cleansing a street of a given length?—I once contracted to remove the stuff from Bond-street away; each cleansing took four teams and two stands, as it is called; or two teams and one stand, that is, two two horse carts, and one single horse cart standing to be loaded two days in the winter time. The cost of cartage in the winter season for cleansing that street was about 5l. for each cleansing. It was cleansed less frequently than weekly: that street is Macadamised. In the summer-time the expense would be less than one-half. The expense of cleansing the whole of Marylebone, that is, the expense of cartage, is about 2,200l. per annum, the parish finding the sweepers.
“Not to neglect the details into which the Ministry desire us to enter, we observe that the maximum of daily street-sweepings is, in winter, 684 cubic metres; the minimum is 410; the average is 547.
“On the other hand, the velocity of the waters of the Seine, measured at their lowest level, being 6 decimetres 5 centimetres a second, and the profile of the Seine, measured also at low water, at the bridge of the Revolution, being 118 metres, we observe that there results, supposing an uniform velocity in the whole mass, a flow of water of 76 cubic metres a second; and in one day a flow of water 9,600 times greater at low water than the most considerable volume of the street-sweepings of Paris for the same space of time. This volume of water would be 16,015 times greater than that of the street-sweepings, if compared with the minimum of these last; that is to say, with the sweepings in summer, or the time at which the waters of the Seine are lowest. Any error in the calculation, arising from the inequality of the velocity in the different parts of the column formed by the current, is too amply compensated by other circumstances to need our consideration.
“To this is to be added, that the season when the street-sweepings are greatest, necessarily accords, all other things being equal, with the period when the water is highest and most rapid, as the period of low water answers to that when the refuse is least; and admitting the preceding calculations, the volume of water would be more than 16,000 times greater than the street-sweepings; and this proportion would increase considerably when the water is highest, by reason of the double proportion of height and velocity.
“It is to be further considered, that a great portion of these sweepings being insoluble in the water, would become precipitated, and unite with the mud; that a larger portion still, deposited unequally on the two banks, would never reach the bleaching-grounds, or the places where the water is drawn, and that consequently their possible relation to the water used in the city, reduces itself to a quantity excessively small, and absolutely inappreciable.”
Dear Sir,—Agreeable to promise, I forward the following observations on the improvement of large towns, as affecting the health, economy, and comfort of the inhabitants, and so far as these depend on structural arrangement.
The points requiring the attention of the engineer and architect may be stated as follows:—complete ventilation, complete drainage, ample sewerage, ample supply of water, and lastly, a ready and good communication between the various portions of the town.
I should have commenced my observations with the subject of drainage as the first in point of order were a new district or town to be built, but as both drainage, and ventilation, and communication, &c., depend so much on the arrangement of the streets, it may not be superfluous to premise something on that head. It will be sufficiently obvious that where towns are constructed on a regular plan with straight streets, the communication, ventilation, and drainage is comparatively easy, and far more effectual than under contrary circumstances; but it unfortunately happens that our large towns contain many narrow, crooked streets, with little or no arrangement, and though it may not be practicable materially to mend what we now find so bad, we cannot fail to perceive that a little timeous system and arrangement would have avoided many evils we now complain of, with a less structural expense and a much improved value of property to the owners.
Many or most of the towns, both in British and Spanish America, are formed on regular plans, commencing with a square as a nucleus, to the faces of which the streets (as they rise) are made parallel, so that whatever may be the extent of the town the increments take place in regular order, until stopped by some natural obstruction; and though it may be true we cannot now enjoy the good effect of any such original precaution, yet as respects the extension or future increments of our cities and towns, much benefit may still be derived by resorting to system; and though we cannot now remodel what has been built by proceeding regularly from a central point to the circumference, yet we may adopt an external line or periphery as a basis of operation for the construction of the future extension of the town on a regular plan or system.
It is fortunate for the metropolis that there existed some large landowners in its vicinity, as the families of Bedford, Grosvenor, and Portman, whose taste and spirit corresponded with their means, and that large portions of the increments of London consequently possess all the advantages that a well-considered system of utility could require; and the benefit of such a circumstance will be best felt by contemplating what effects a contrary proceeding would have produced; and further, the plans pursued by the above-named families have not only been highly beneficial in themselves, but they have served to stimulate the small proprietors in their vicinity to the same useful ends; and what seems to be wanted from the authority of the state is the means of ensuring such beneficial measures in all cases, or at least protection against antagonist or vicious proceedings in the owners of land adjoining towns.
It will not fail to be remarked that the increments of London just alluded to have been constructed chiefly for the abodes of the wealthy, who can generally protect themselves, and remove from any noxious neighbourhood. But the state, as the natural guardian of the poor, is the more called upon to interfere with its authority to see that the streets and houses intended for the labouring classes are constructed on comfortable and sanitary principles.
Most of our large towns have increased upon small, irregular nuclei, and received their increments chiefly from buildings erected along the roads branching into the country, presenting so many main streets radiating from a centre, but leaving the intervening spaces to be irregularly and imperfectly filled up at subsequent periods as chance or necessity directed, and in this manner has arisen the great defect (to be generally observed) of a good lateral connexion between the great radiating streets.
So great indeed is the above defect that it is often difficult to pass from one site in the skirts of a town to an adjacent one without passing towards the centre of the town by one radiating street and returning by another; this defective construction of towns is the natural result when they extend without any reference to a general plan or public convenience, and the mode which, in my opinion, would best restore the condition of a town so constructed to a commodious and useful state would be as follows:
I would propose, in the first instance, to connect all the radiating streets of the town by straight lines drawn as near to the mass of buildings in the town as the vacant or unbuilt ground would admit of; this operation would have the effect of inclosing the town in an irregular polygon, upon each side of which, as a normal line, I would propose to lay out the future streets, one series of which would be parallel to the normal lines, and another series would be perpendicular to them, and in this manner the future increments of the town would proceed on a fixed and uniform system, and would render the lateral lines of communication as effective as the others, and would afford at the same time increased facilities for ventilation and sewerage, and for the supplies of water, gas, &c.; and proceeding on this system, it may fully be anticipated that the building sites would become much more valuable to their owners than if they remained to be laid out by individual caprice on a disjointed plan. It would be valuable in most cases that the normal polygon should be formed into a series of streets of ample dimensions, fit for the reception of public buildings, particularly schools; and occurring (as it would do) as the nearest great lateral line of communication to the irregular mass of the town, it would serve to do much of the duty in way of communication and ventilation which the interior mass had left undone, and was unable to effect, and might answer as the great respiratory of the town, and would be well adapted to serve, if wide enough, and planted, for alamedas, or public walks.
In London, the line of the New Road and City Road furnishes almost the only sample the metropolis possesses of polygon lines of communication, and the utility of the sample is duly felt and appreciated. In Paris the line of the Boulevards presents a favourable specimen of the convenience and comfort of such a construction of streets.
The advantage of adhering to system in laying out new towns, or additions to old towns, will be much enhanced when we take into consideration the means of supplying water, gas, &c. to the houses; and as the application of science and machinery becomes more extended in administering to the comforts of towns, it is manifest the more regular the field of their action the more efficacious and economical will be the results. On the score of ventilation, as well as for other conveniences, it is important the streets should intersect and not abut on each other, that the currents of air may have free escape.[49]
One of the greatest evils arising from towns extending at caprice, without reference to any general plan, is the vast expense that subsequently arises when necessity demands communications to be made through crowded masses of buildings; such events are of frequent occurrence in the metropolis and other large towns, and so great is the outlay to remedy what might have been avoided, that no measures proposed for the improvement of towns merit such deep attention as these; and it has sometimes occurred to me, that instead of applying the funds to enlarging the leading thoroughfares, the object would in many cases be better served by forming entirely new communications through the worst constructed and less costly sites. In this manner we should have two good communications instead of one; we should open the means of communication, ventilation, and sewerage to places where at present they exist most imperfectly, and we should expunge from the map of the town a number of noxious, ill-ventilated ruinous buildings, the seats of dirt, disease, and demoralization.
Annexed is a plan of the town of Birmingham, on which is traced a study or design for the future increments of that town on the principles above proposed, which will serve to illustrate the views of the writer. The figure P P P P represents the normal polygon.
Increments.—It is hardly to be expected that any very uniform plan of building can be rigidly adhered to; moral as well as physical difficulties may demand departure from regularity in the construction of the future increments of a town, particularly where the field to be occupied is extensive; but so long as the general principles are adhered to, and the new streets proceeded with, upon a general preconceived and authorized plan, all the needful objects may be attained; and it has occurred to me that the mode most likely to give satisfaction to the inhabitants would be for the municipal authorities to offer a premium for the best design for the extension of the town, and of leaving the selection to the majority of the ratepayers.