The effective watering of streets and roads in any town during the summer months is an important matter, not only on sanitary grounds, but also from the fact that considerable damage may be caused in the neighbouring shops, warehouses, and dwellings, if something is not done to prevent the clouds of detritus and decaying refuse, of which the dust is composed, from being blown about. In the metropolis of London alone, the watering of the streets and roads employs, in addition to a staff of surveyors, inspectors, and foremen, about 1,500 men, and an equal number of horses and carts; and in order to lay the dust effectually, about 30,000 tons of water must be spread upon the streets every dry day, the cost of this gigantic work being nearly £200,000 per annum upon an average of 120 days, when watering becomes necessary.

The most commonly known method in this country for watering the streets and roads of our towns is that of carrying the water in wheeled barrels, carts, or vans, and distributing it therefrom through a perforated pipe upon the surface of the road as the vehicle is drawn along by a horse attached to the shafts.

The points of importance to be considered under this system are as follows:—

(1.) The number and position of the stand posts or hydrants, from which the water carts are to be filled, and whether they shall be "swan neck" stand posts or "valve" hydrants.

(2.) The size and form of the body of the water carts, as regards its cubical capacity, its weight, strength, lightness of draught, durability, width of spread, and shape of jet, so as to ensure evenness of supply without leaving pools of water or dry patches after it has passed, or causing that unpleasant cloud of dust which so often follows the cart.

A wonderful improvement in all these respects has been lately effected by the introduction of Mr. E. H. Bayley's Patent Hydrostatic Van, of which I shall speak more in detail hereafter.

(3.) Another point of some importance is the material of which the hose shall be constructed, if valve hydrants and not swan necks are existing. My opinion is that it should be of leather, as being roughly handled and little cared for; canvass hose, although the cheapest, is not sufficiently durable, and is consequently the dearest in the end; and (4), lastly, the driver and horse should both be of some intelligence. A check should also, if possible, be kept upon the former to see that he performs his allotted task, and does his proper number of rounds. Mr. Bayley has also introduced for this purpose a "Tell Tale Indicator," which records automatically the quantity of water used; it cannot be tampered with, and registers on a dial outside the van each load of water delivered, so that the surveyor or other officer can see at a glance whether the driver is attending to his work, or whether the hot weather has made him find his throat drier than the roads, and he has been spending some of his time in moistening it. In the year 1856, Mr. Scott, C.E., the chief surveyor of the parish of St. Pancras, kept an account of the daily round of an ordinary water cart, when he found that through an average working day of 10¼ hours, exclusive of the breakfast and dinner hours, the cart took one hour and twenty minutes filling, fifty minutes only in distributing the water on the roads, and eight hours and seven minutes in travelling to spread the water and back to the stand posts. It was obvious that these were placed too far apart, and by the subsequent introduction of additional standposts Mr. Scott found, in the year 1867, that the filling occupied two hours, the distribution one hour and thirty minutes, and the travelling to and fro six hours and thirty minutes, so that it may be assumed, with an ordinary two-wheeled water cart, that two-thirds of the day is spent in travelling, one-fifth in filling, and about one-seventh in the actual spreading.

To many of my readers Bayley's Van is probably as familiar as it is to me, but it may notwithstanding be well to describe it. It is a handsome vehicle in appearance, the body being made of wrought iron plates, and measures 8 ft. in length by 4 ft. 8 in. in breadth, and 2 ft. in depth, holding 450 gallons. It is mounted on springs upon four wheels hung upon Bayley's patent axles, and has a pair of light shafts; it can easily be fitted with a break for hilly roads, and there being no weight at any time upon the horse's back, he is relieved from any severe strains.

By means of an adjustable valve the flow of water can be regulated according to the state of the roads, and, if necessary, a double valve can be inserted, so that either side of the distributor can be at work when only half the width is required, or when passing a carriage or narrow spaces.

The branch pipe is of uniform size, except close to the spreader, where it enlarges in order to avoid friction, and this is assisted by the branch pipe being shaped into a cycloidal curve on each side.

In order to obtain as great a pressure as possible upon the jets of the distributing pipe, and thus to give the side jets a greater trajectory than they otherwise would have, the tank is elevated as high as is consistent with the conditions of draught. At the same time, the distributing pipes are placed as near to the ground as convenient, so that the maximum extent of distribution is obtained, and that with less dust and splashing than in the ordinary system. The holes in the distributing pipe instead of being drilled in straight lines, are on a curved line, which rises along the length of the pipe from the centre towards the ends. This has been found necessary, in order that the distributing pipe may be placed low, and at the same time advantage be taken of the width of the trajectory of the jets.

Comparing the work of one of these vans with that reported upon by Mr. Scott, it is found that the van occupies nine minutes in filling, six minutes in spreading the water, and only three hours and fifteen minutes in travelling to and fro, so that in seven hours it accomplishes as much work as the ordinary water cart effects in ten hours.

In Edinburgh, where a trial of one of these vans took place against one of the old carts, it was found that the van spread the water a width of 20 feet, while the old cart only covered 14 feet; the van conveyed the water 1,731 feet, and the cart only 951 feet. The superficial area watered by one load of the van was 34,620 feet, and by the old system only 13,314 feet. When we consider the time that is lost in travelling to and from the stand pipe, what a large saving this represents in the cost of this work.

Mr. Tomkins, C.E., the surveyor of the important Metropolitan parish of St. George, Hanover Square, has made the following comparative experiments with one of Bayley's vans as against an ordinary cart:—

This shows a mean gain of 26 per cent. in favour of the van, and the following tables made by an inspector in 1873, showing the actual occupation of the ordinary carts and Bayley's vans during a day's work, are extremely interesting, as showing that while the van is engaged in spreading the water the time of the cart is wasted in travelling to and from the stand posts, and when it is borne in mind also that the van spreads water more widely than the cart, there can be no doubt that a saving of at least 30 per cent. can be effected by the substitution of these vans for the old-fashioned cart.

One of the earliest methods for watering streets, but one which has, I think, almost entirely died out on account principally of the large quantity of water used in the process, was that of allowing the water to run down the channel gutters, ponding it back by means of canvass or leather aprons placed across the gutter, and then spreading the water on to the surface of the street by throwing it with wooden shovels.

This method, although at first sight may appear clumsy, is an exceedingly good one upon sanitary grounds. It not only lays the dust, but it washes the surface of the streets, and it most effectually scours out the gutters and at the same time flushes the sewers, which at the season that watering is necessary is also of great importance to any town. By this process a delightful freshness is given to the air, and the appearance of the cool and limpid water rushing along on each side of the street acts favorably upon the inhabitants. The great objections to this system are the enormous quantity of water that is used in the process, and the difficulty of doing the work after the traffic of the day has commenced. Somewhat of a modification of this process is what is known as "Brown's System of Street Watering," which may be described as follows:—A lead pipe is laid in the footpath at the back of the kerb on each side of the street to be watered, small gratings or shields being fixed in the pipe at intervals of twelve inches, and the remaining space filled with asphalte; small holes are then bored in the pipe through the openings in the shields. The pipe is connected with the water main in the street, and is provided with the necessary stopcocks, &c.

On the water being turned on, fine jets are thrown in different directions upon the surface of the street.

The width of roadway that can be watered by this process depends upon the pressure of the water, but it may be fairly assumed that in most towns streets of fifty feet width could be effectually watered in a few minutes by a pipe on each side of the street.

This process has not gained much favour hitherto, principally on account of the large first cost involved, which would amount to upwards of £800 per mile of street, but the expense afterwards should not much exceed the wages of one man at about 3s. 6d. per day to manipulate the necessary work, and the interest on the outlay and depreciation of the pipes, &c.

The other objections to this system are:—

(1.) The liability of the pipes and perforations to get out of order, especially when allowed to lie idle for so many months in each year.

(2.) The unpleasantness to pedestrians which must be caused whilst the watering is proceeding.

(3.) The inconvenience to the traffic during the process.

(4.) The effect upon the water by high winds, when in all probability it would be blown back across the foot pavements.

(5.) In very broad streets it would be inoperative.

In Paris and other continental cities, and also in several towns in this country, the watering is effected by hose and reels, or by portable iron tubes.

Mr. Parry, C.E., the borough surveyor of Reading, has given the following particulars of the system of hand watering adopted in that borough, in which he gives the cost, and describes the utility of that method as compared with the use of water carts:—

A water cart (he states) will water twice a day a superficial area of 23,849 yards, and for a length watered one width that means 5,962 lineal yards, or for a double width 2,981 yards, the cost per day of laying on being as follows:—Horse, cart, and man, 8s.; cost of maintenance of cart, harness, shoeing, &c., 1s. 5d., making 9s. 5d. per day.

With respect to the hand machines he states that he has one of Headley's drum machines, and three of special make, somewhat similar to those used in Paris. They are equal in point of work; and one machine will water 23,740 square yards twice a day, which, it will be observed, is very close to the amount of work performed by a cart.

"Headley's machine cost us (he continues), five years ago when new, £31 7s. 3d., and the repairs and maintenance since that date have been £22, or an average of £4 8s. per annum, and is just now almost past repair. The other description of hand machine cost each when new £20, and the repairs and maintenance have amounted to an average of £3 18s. each year. They were in use sometime before Headley's was obtained, and they will be of use for a long time yet. The cost of labour per day by the hand machines is for two men at 2s. 10d. each—5s. 8d.—as it requires two men to work the machine properly, one to distribute the water, and the other to move the machine and to attach and detach the apparatus to and from the hydrants; add to this 7d. per day for maintenance and repairs, will make 6s. 3d. per day. The quantity of water delivered by the water carts is 0.51 gallon per square yard, and by the hand machine 1.30 gallons."

It will thus be seen that in the case of the cart 24,324 gallons of water are used per diem, and 61,724 gallons by the hand machines, the surface watered being very nearly the same in both cases. Assuming that the water has a commercial value of 6d. per 1,000 gallons, and adding this to the cost per diem in each case, the total cost stands thus:—

the advantage in point of cost being in favour of the carts, but the hand machine may water better, especially in broad streets, although in narrow streets or where there is much traffic, this method would be impracticable.

In Paris both hose and carts are used for watering the thoroughfares, the former for the boulevards, the avenues, and a certain number of first-class streets. The watering plant belongs to the municipality, and they have various forms of carts, containing 220, 242 and 286 gallons respectively, and will water from 2,400 to 3,350 square yards. The watering by hose is attended to by the ordinary street cleaners, who can easily water 24,000 square yards in about thirty-five minutes, deducting the time necessary to connect the apparatus with the mains, but this requires a gymnastic performance, which, if once seen, is not easily forgotten.

Watering the streets with sea water should be adopted whenever it is feasible, as it not only gives a delightful freshness to the air and dispels iodine, but it also causes the surface of the street to maintain its humidity for a longer period than when fresh water is used, as it impregnates the soil with hygrometric matter.

This has been often attempted artificially, not only by adding common salt to the water used for watering, but also by adding chloride of calcium, notably in Rouen, where this material is obtained from the manufactories of pyroligenous acid in the neighbourhood. It is stated that on a mile of road, 16 feet in width, 5,630 gallons of water were necessary daily, but that the same result was attained with 1,480 gallons of chloride solution, marking 30° BeaumÉ, and costing about ½d. per gallon, the humectation remaining good for five or six days with the solution of chloride. With water only in 1,093 yards, in four rounds daily, 3,520 gallons were used, the cost being 48s.; with chloride of calcium the cost was 32s. per day.

Watering the roads with a largely diluted disinfectant, such as "Sanitas" in the liquid form, is frequently of great benefit, and where it can be afforded, it should be occasionally done, especially in the narrower streets and more crowded districts of a city or town.