Clean well-swept streets not only add materially to the prosperous appearance of a town, but they also have a very marked influence upon its health and upon the morale of its inhabitants; wet, and muddy, badly formed, ill-drained streets, cause dampness in the subsoil of the dwelling-houses in the vicinity, and a humidity in the atmosphere, both of which tend to produce a low standard of health in their neighbourhood, irrespective of the wet surface through which pedestrians have to wade whenever they are obliged to cross such streets. Dusty streets, too, are very injurious from the fact of persons inhaling the gritty silicate loaded air arising from them; such an atmosphere is known to produce disease of the lungs, even when it is free from the dust arising from horse droppings or other organic impurities. Professor Tyndall, in his beautiful experiments, has proved that dusty air is alive with the germs of the bacteria of putrefaction, whilst the pure fresh air which he gathered on a mountain peak in the Alps is innocent of such germs, and is absolutely powerless to produce any organisms. Persons living in streets that are improperly swept or watered are unable to open the doors or windows of their houses with impunity by reason of the dust.

The definition of the word street, as given in the Public Health Act, 1875, is as follows:—"Street includes any highway (not being a turnpike road), and any public bridge (not being a county bridge), and any road, lane, footway, square, court, alley, or passage, whether a thoroughfare or not."

With reference to turnpike roads the Act further states that any Urban Authority may by agreement with the Trustees of any turnpike road, or with the Surveyor of any county bridge, take on themselves the maintenance, repair, cleansing, or watering of such street or road.

It is very questionable, however, whether the onus of cleansing private courts and alleys which are not repairable by the Urban Authority should be borne by them, although for the sake of the public health it is highly desirable that such work should be so undertaken.

The great difficulty attached to this duty arises from the fact that as a rule these private courts and alleys are very badly paved, if paved at all, full of pits, where pools of stagnant mud and water collect, and even in the best cases, the interstices between the pebbles, or other paving, are filled with filth arising in great measure from the dirty habits of the people, and this filth it is found exceedingly difficult to dislodge. The remedy for this is to compel the owners of the abutting properties to have the courts and alleys properly paved with asphalte, or other equally impervious material, after which it would be easy for the Urban Authority to cause them to be swept at least once a day, and flushed with water in the hot weather once a week, but in order to compel the owners to execute this very desirable work it would be necessary to put the complicated machinery of section 150 of the Public Health Act, 1875, in force, and the expense to the landlords would be in many cases very disproportionate to the value of their property.

Out of the ninety towns to which reference has before been made, the authorities of only nineteen of them cleanse the private courts and alleys in their jurisdiction. The sweeping and cleansing of streets should be effected either at night or very early in the morning; if, however, the bad practice of bringing the house refuse out into the streets in inappropriate receptacles is in vogue, it becomes necessary to sweep the street later in the day, after the contents of these receptacles has been removed. In most cases it is necessary to cleanse the principal streets of a town at least once a day, and this appears to be the practice of nearly all the ninety towns referred to, but only seven of them appear to have this operation repeated more frequently; in several cases, however, the horse droppings, &c., are removed at once, under what is called the "orderly" system, and this is especially necessary in streets that are paved with such materials as wood paving, asphalte, or granite setts. The suburban streets of a town need only be cleansed once or twice a week, except in special cases of extremes of mud or snow. It is important, however, that the gully pits in all parts of the town should be cleared out constantly, and men should be employed for this purpose, as well as to cleanse and disinfect all the cabstands and public urinals at least once every day.

Street cleansing is effected either by hand-sweeping and hand-scraping, or by machinery. As to which is the most economical much depends upon the value of labour, and also upon the condition of the roads to be dealt with, but in point of time and as a general rule the value of a horse rotary brush-sweeping machine is undoubted, the only time at which such a machine fails to do effective work is on the occasions when the mud to be removed (owing to a peculiar condition of the atmosphere), has attained a semi-solidity, and is of a stiff and sticky consistency, when it either adheres to and clogs the brushes of the machine, or is flattened by them on to the road instead of being removed.

The simplest and best of these machines, in my opinion, is that manufactured by Messrs. Smith & Sons, of Barnard Castle. It sweeps a clear width of six feet, the rotary brush, which is divided into four or more parts, works diagonally, it is drawn easily by one horse, clearing itself of mud or dust in its progress, and the makers say that it can sweep 15,000 square yards of road surface in one hour, this being equivalent to the ordinary work of about 50 men in the same time!

The price of this machine is £30, and being of very simple construction it costs little or nothing in repairs, except for the brushes, which last for about 180 hours when in constant work. These can, however, be replaced at a cost of £2 15s. per set, or the old stocks can be refilled with bass, at a more moderate figure. It is, of course, necessary to sweep the ridge of dust or mud which is left by the machine at the side of the street into heaps by hand labour, and to remove it by carts; other machines have been invented for cleansing streets, which by means of elevators, or other gear, profess to raise the mud or dust direct into the carts, which are to be attached at the back of the machine, but hitherto these machines have been found to be too cumbersome, costly, and complicated for the purpose, and they have not consequently found much favour with Sanitary Authorities.

Messrs. Smith & Sons also construct a patent road scraping machine, which is drawn by one horse, and which will, they say, scrape upwards of 10,000 square yards of road surface in an hour.

The strength and durability of the hand brooms purchased by an Urban Authority for the work of sweeping the streets is of some importance, as affecting the ultimate cost of the work, and some care and skill is required in their selection.

Bass brooms are better than birch brooms for this purpose, and the bass of which the brooms are made should be sufficiently stout and of regular thickness; it should be tough and elastic, not old, dry, and brittle, each knot should be of uniform size and be firmly set, and the number of knots in each broom head is also a matter of choice. A convenient and fair test of the soundness of a broom is to soak it for a few days in water before issuing it to the sweeper, and then note the time it will last. The handles of the brooms should be made of alder wood.

The mode of construction of streets, and the materials of which they are formed, makes a considerable difference in the amount of cleansing necessary, and upon the quantity of mud or dust that has to be removed from their surface. In making any investigations for the purpose of deciding what difference exists in the question of cleansing various forms and descriptions of pavements, climatic influence introduces a rather disturbing element, which may seriously affect any conclusions that may be drawn; it may, however, be taken for granted that a street, the surface of which is metalled on the macadam principle with stones of a soft or gritty character, will require more cleansing and be more costly to scavenge (under the same conditions of climate and traffic), than a street paved with the hardest granite setts or with blocks of wood, or with asphalte, and at the same time much care will have to be taken not to over sweep or over scrape a road with a macadamised surface, or much injury will be done to it.

Amongst the influences that disturb the results of any investigations made with respect to street cleansing, that of the amount and character of the traffic over it must not be lost sight of, and the state of repair and gradient of the street are both of considerable importance in affecting the results, the practice too, of bringing out the house refuse into the streets in improper receptacles pending the arrival of the scavengers' cart, must also cause a varying amount of refuse to be swept from its surface, depending upon the habits of the persons living in the street.

The Superintendent of the Scavenging Department at Liverpool has made some observations and obtained some valuable information on these points, which he has detailed in a report he presented to the Health Committee of that borough in the year 1877, an abstract of which is as follows:—

GROSS COST FOR EACH TIME OF CLEANSING 10,000 YARDS SUPERFICIAL OF DIFFERENT DESCRIPTIONS OF ROADWAY IN THE BOROUGH OF LIVERPOOL.

He adds that the full benefit of the impervious pavements as regards the cost of scavenging has not yet been felt, for almost all the lines of streets so paved are intersected at short distances by streets of ordinary jointed granite setts or macadam, whence a quantity of mud and refuse is dragged by the traffic on to the asphalted jointed roadways, which are consequently debited with the cost of removal of some effete material not intrinsically belonging to them. He further adds that the credit reductions to be made in respect of the value of manure obtained from each description of carriageway is not readily ascertainable. In dry weather the value of manure collected from granite setts, with or without impervious joints, is about equal, but when the sweepings are wet, and consequently of little value for sale, the quantity yielded by the ordinary pervious jointed pavement is greater than from the impervious, and therefore the total value is relatively favourable to the latter class, whilst to get rid of the sweepings from macadamised streets is a source of additional expense. He concludes this portion of his valuable report by observing that the advantages of the new impervious pavements over the old kinds are especially shown after frost and snowfall, the results of which cause the setts of ordinarily jointed roadways to become loose, and allow a vast amount of mud to ooze up between the softened joints. The comparison is still more apparent in regard to macadam, which, unless a heavy rainfall succeeds the thaw, cannot be swept for some days without great destruction being caused to the metalling of the roadway.

The ultimate disposal of the material removed from the surface of a macadamised roadway, being principally composed of silicate, and consequently valueless as a manure, is a difficult matter.

In small towns, except during abnormally muddy weather, it may be mixed with the house refuse and sold to farmers, or the road scrapings themselves may be used as an excellent sand, if thoroughly washed, to mix with lime or cement to form mortar for public works; excessive accumulations of mud, however, must be got rid of in the most economical and speedy manner, and this is effected either by filling up old disused quarries with it, or depositing it upon waste lands, or forming embankments for new roads, but in no case should it be used, as I have before stated, upon building sites; it is difficult and expensive to destroy it or partially convert it into other matters by fire, so that if these methods which I have enumerated are impracticable, the only other method left for the disposal of the sweepings or scrapings from the streets is to take them out to sea in hopper barges and sink them in deep water.

In the City of Paris an area of about 13,000,000 square yards of streets are cleansed between three and six a.m. in the summer months and four and seven in the winter. This work in connection with the collection of the house refuse employs 2,200 men, 950 women, and 30 boys, besides 190 mechanical sweepers.

The Paris mud is said to no longer possess the manurial strength of former times, and in consequence the receipts derived by the municipality from this source have greatly diminished. At the present time it is disposed of by public tender to responsible contractors, who manage to take between them some 2,500 cubic yards daily.

The following additional particulars of the manner in which this work is carried out in Paris will, I think, prove of interest, especially with regard to the use of disinfectants, which are largely used in that city in connection with the cleansing of the streets, a practice which might be followed with advantage by the Sanitary Authorities of this country.

The cleansing of the public thoroughfares in Paris, which was formerly undertaken by the Prefect of Police, is now a function of the Prefect of the Seine. The staff consists of two chief engineers, one for each group of arrondissements, one group being sub-divided into three sections, each under the charge of an executive engineer, and the other into five sections similarly supervised. These sectional engineers have under them 51 superintendents and 61 overseers, whose employment costs annually £10,400. The scavenging plant is kept in a central depÔt, where materials of every description are stored and classified for ordinary and extraordinary service, when snow and ice render additional assistants necessary.

The depÔts contain supplies of chloride of lime, sulphate of zinc, sulphate of iron, and carbolic acid, as disinfectants; and hydrochloric acid and nitrobenzide, as cleansing agents. The chloride of lime, of a strength of 100° to 105°, is successfully employed for the disinfecting of places tainted with urine or faecal matter, also for cleansing gutters carrying any sewage water. Sulphate of iron and sulphate of zinc are both used under the same conditions. Sulphate of iron has the disadvantage of rusting objects to which it is applied, sulphate of zinc is stronger in its action, but it costs a little more; it produces no smell, nor does it leave any stain; it is much employed in summer for washing and watering the basements of the "Halles Centrales," which are used for fish, poultry, and offal. At a strength of one-eighth, and mixed with three per cent. of sulphate of copper, sulphate of zinc makes a good disinfecting liquor, which preserves its qualities a long time, and is of great use in private houses. Carbolic acid is not, strictly speaking, a disinfectant; it does not act like chloride on putrid matter, but it arrests and prevents fermentation, doubtless by destroying the spores, it is, therefore, always employed when it is desired to destroy the germs of putrid fermentation. It is used at a strength of about one-fortieth, say a gallon of acid to 40 gallons of water. At strengths of one-one hundredth and one-two hundredth it gives good results for watering once or twice a week in summer those parts of the "Halles Centrales" liable to infection; it is even used as low as one-one thousandth for watering streets and gutters. Hydrochloric acid is applied to urinals and slaughter-houses, in places much encrusted with tartar; it is used at a strength of one-sixth, lowered to one-tenth, it cleans smooth walls and flags efficiently, in ordinary rinsings a strength of one-fifteenth suffices; it leaves a disagreeable odour behind, which is, however, quickly dissipated. Nitrobenzide is more energetic than the foregoing, but it produces a disagreeable smell of bitter almonds and leaves a white film, which has to be washed off; it is used at the same strengths as hydrochloric acid. The annual cost for plant and disinfecting materials of all descriptions is £8,800.