Part 56

I beg leave further to suggest, that the principles of amendment deduced from the inquiry will be found as applicable to Scotland as to England; and if so, it may be submitted for attention whether it might not be represented that the structural arrangements for drainage would be most conveniently carried out in the same form as in England, that is by commissions, of the nature of commissions of sewers adapted, as regards jurisdiction to natural or geological areas, and including in them the chief elected officers of municipalities, and other authorities now charged with the care of the streets and roads or connected with local public works.

The advantages of uniformity in legislation and in the executive machinery, and of doing the same things in the same way (choosing the best), and calling the same officers, proceedings, and things by the same names, will only be appreciated by those who have observed the extensive public loss occasioned by the legislation for towns which makes them independent of beneficent, as of what perhaps might have been deemed formerly aggressive legislation. There are various sanitary regulations, and especially those for cleansing, directed to be observed in “every town except Berwick and Carlisle;” a course of legislation which, had it been efficient for England, would have left Berwick and Carlisle distinguished by the oppression of common evils intended to be remedied. It was the subject, of public complaint, at Glasgow and in other parts of Scotland, that independence and separation in the form of general legislation separated the people from their share of the greatest amount of legislative attention, or excluded them from common interest and from the common advantages of protective measures. It was, for example, the subject of particular complaint, that whilst the labouring population of England and Ireland had received the advantages of public legislative provision for a general vaccination, the labouring classes in Scotland were still left exposed to the ravages of the small-pox. It was also complained by Dr. Cowan and other members of the medical profession, that Scotland had not been included in the provisions for the registration of the causes of death which they considered might, with improvements, be made highly conducive to the advancement of medical science and the means of protecting the public health.

I have the honour to be, Gentlemen, Your obedient servant, EDWIN CHADWICK.

APPENDIX.

1.—_Evidence of_ MR. JOHN ROE, _Civil Engineer, on the Practical Improvement in Sewerage and Drainage tried in the Holborn and Finsbury Divisions of the Metropolis_.

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 11_s._ per cubic yard of slop removed; where they have man-holes it was 6_s._ 10_d._ 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 6_d._ to 1_s._ 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 1200_l._ per annum; we save 600_l._ 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 300_l._ 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 10_s._ 6_d._ per foot lineal; which is 7_s._ 6_d._ 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, 4_s._ 6_d._ 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 3_l._ 16_s._ 2_d._

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 5_l._ 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.