CHAPTER III.
THE SURVEYOR’S DUTIES.

It will be observed on reference to the list of the duties of the surveyor, given in the preceding chapter, that the first on the list is as follows:—

“To have charge of the repairs of all highways, and to perform all duties devolving on the council as surveyors of highways.”

The necessity for these duties are obvious when we turn to the Public Health Act 1875, and read the following sections:—[6]

“Every urban authority shall within their district, exclusively of any other person, execute the office of and be surveyor of highways, and have, exercise, and be subject to all the powers, authorities, duties, and liabilities of surveyors of highways under the law for the time being in force, save so far as such powers, authorities, or duties are or may be inconsistent with the provisions of this Act; every urban authority shall also have, exercise, and be subject to all the powers, authorities, duties, and liabilities which by the Highway Act 1835, or any Act amending the same, are vested in and given to the inhabitants in vestry assembled of any parish within their district.

“All ministerial acts required by any Act of Parliament to be done by or to the surveyor of highways may be done by or to the surveyor of the urban authority, or by or to such other person as they may appoint” (38 & 39 Vic. c. 55, s. 144).

“All streets being or which at any time become highways repairable by the inhabitants at large within any urban district, and the pavements, stones, and other materials thereof, and all buildings, implements, and other things provided for the purposes thereof, shall vest in and be under the control of the urban authority. The urban authority shall from time to time cause all such streets to be levelled, paved, metalled, flagged, channelled, altered, and repaired as occasion may require; they may from time to time cause the soil of any such street to be raised, lowered, or altered as they may think fit, and may place and may keep in repair fences and posts for the safety of foot-passengers. Any person who without the consent of the urban authority wilfully displaces, or takes up, or who injures the pavement, stones, material, fences, or posts of, or the trees in, any such street shall be liable to a penalty not exceeding five pounds, and to a further penalty not exceeding five shillings for every square foot of pavement, stones, or other materials so displaced, taken up, or injured; he shall also be liable, in the case of any injury to trees, to pay to the local authority such amount of compensation as the court may award” (38 & 39 Vic. c. 55, s. 149).

The duties thus devolving upon the town surveyor by reason of these sections and the orders of the council are very considerable. The following table gives a list of the principal subjects which will require his attention; all of which will be considered in due course in this book.

List of Duties devolving upon a Town Surveyor as “Surveyor of Highways.”

 (1.) The construction and maintenance of highways or streets, including—

 (2.) The construction and maintenance of footwalks or footpaths, including the different materials of which these are formed.

 (3.) The breaking of stone for road metal.

 (4.) Steam rolling.

 (5.) The necessary notices and specifications under the 150th Section of the Public Health Act 1875, for the purpose of compelling private streets to be properly sewered, levelled, paved, metalled, flagged, channelled, lighted, and made good.

 (6.) The lighting, cleansing, and watering of streets.

 (7.) The naming and numbering of streets.

 (8.) The planting of trees along the sides of footwalks.

 (9.) Obstructions caused by builders’ rubbish or by hoardings and scaffold poles; and also by dangerous or defective cellar coverings.

(10.) The damage caused to footpaths by allowing water from private premises to flow over them, and the nuisance caused by defective rain-water gutters or shutes.

(11.) The damage caused to roadways by the laying or removal of gas and water mains and services, and the surveyor’s powers and duties in connection therewith.

(12.) The importance, especially in old towns, of laying down improved building lines of frontage in the narrower or crooked streets.

(13.) The examination of all plans of proposed new streets or buildings.

(14.) The supervision of all new streets and buildings whilst their construction is in progress.

(15.) Dealing with all buildings in a condition dangerous to the public.

Each of the foregoing list of duties will be dealt with in separate chapters in addition to other matters which will be treated, but before closing this chapter a few words upon the subject of “meetings” may be of use.

It will be observed upon reference to the list which I have given of the duties of the surveyor, that there is one which says, “To attend all meetings of the board, and committee meetings, except where his attendance has been previously dispensed with; to attend upon the chairman when so required.”

The result of this order is that a very large percentage of the surveyor’s time has to be devoted to attendances at long meetings of the Board or town council, and at the numerous committee and sub-committee meetings which are appointed under it.

This work is doubled where, as in some towns, the corporation and their committees sit in a dual capacity, viz. as the council proper, and the council as the urban sanitary authority; this generally involves two ordinary meetings of the whole body each month, and probably at least six committee meetings a week, leaving the surveyor but scanty time to look properly after his works.

With regard to these committee meetings it is necessary that each should have some distinguishing title descriptive of the class of work over which it has jurisdiction, and in selecting names for them the following list may be of some service:—Finance Committee, General Purposes Committee, Law and Parliamentary Committee, Surveyor’s Committee, Land and Estates Committee, Rates and Taxes Committee, Streets Committee, Lighting and Cleansing Committee, Navigation of Port Committee, Public Grounds Committee, Sanitary Committee, Drainage and Sewerage Committee, Markets Committee, Properties for Sale Committee, Works Committee, Water Committee, Gas Committee, Watch Committee, Health Committee, Library Museum and Arts Committee, Baths Committee, Parks, Gardens, and Improvement Committee, Streets Improvement Committee, etc. etc.

The surveyor should always endeavour to be punctual in his attendance at the council meetings and those of the committees, as to be late is always looked upon with disfavour. His reports should as much as possible be in writing, so that there should be no misunderstanding as to what his advice is on any subject. To save trouble and expense it is well that all drawings of new schemes should be first submitted to a committee in pencil, as they are frequently much altered; this is very vexing if they have been neatly and highly finished. It must not be forgotten that the gentlemen who form municipal bodies give their time gratuitously, and everything should be done to save it as much as possible. It is an excellent plan and a great convenience, if a surveyor will have a series of named and numbered pigeon holes in his office corresponding to his committees, in which to place all papers, drawings, correspondence etc., which he intends to bring up to the next meeting of a committee; thus saving himself flurry at the last moment before the meeting, in endeavouring to find the papers he wants. With his varied duties, correspondence, interviews, meetings, inspections, investigations, reports, drawings, and calculations, the motto of a surveyor’s office should be “method.”

CHAPTER IV.
TRAFFIC.

Before a surveyor can decide upon the best material with which the streets of his town shall be paved, it will be well to consider the question of the class of traffic they will have to bear.

It must be remembered that three distinct interests have to be considered in dealing with this question, viz. (1.) The rate-payers, upon whom the cost of construction and maintenance of streets falls. (2.) The owners and employers of horses and vehicles who principally use the streets; and (3.) The inhabitants of the adjoining premises, who would be annoyed if the material selected were unduly noisy or dirty. In addition to these considerations, much depends upon local circumstances; the class of trade upon which the welfare of a town is dependent must not be lost sight of. A pavement suitable for a busy, pushing manufacturing city may not be suitable for a quiet agricultural or cathedral town, or for a town which is used as a health resort. Again, the question of the most adaptable materials must be considered, and the climate and physical character of a town should enter largely also into this question.

To condense the requirements of a good roadway into as small a compass as possible, the following may be given as some of its principal requisites:—

 (1.) It must not be extravagantly costly in its first construction.

 (2.) It must be durable and require the least possible amount of repairs at the least cost.

 (3.) It must be safe, firm and hard, with an even face and yet giving sufficient foothold to horses.

 (4.) It must be as noiseless as possible.

 (5.) It must be so constructed as to be quickly laid down and repaired when broken up for water, gas, drains, or other purposes.

 (6.) It must be of strong foundation, so as to carry the heaviest weight without subsidence.

 (7.) It must be of such a shape as will throw off all surface water at once.

 (8.) It must be of such materials as will make a minimum of dust or mud.

 (9.) It must be easily cleansed.

(10.) It must be non-absorbent of impurities or moisture of any kind.

(11.) It must give easy traction upon its surface.

(12.) It must not cause jolting to the traffic.

(13.) It must not injure horses’ legs or hoofs.

Of the above requirements No. 1 affects the ratepayers alone; Nos. 3, 11, 12, 13, affect the traffic only, except that the occupiers of shops are indirectly affected by them; No. 4 affects both traffic and occupiers, and No. 10 affects the occupiers principally. The remainder of the requirements affect all three interests.

With reference to the wearing effect of traffic upon the surface of the roadway, no standard has yet been arrived at by which this can be determined with accuracy. In France a great number of observations and experiments have been made from time to time by the engineers of the Ponts et Chaussées, but their practice has been to count the number of “collars” passing a given section of a roadway in a given time, irrespective of the weights, speeds, or number of wheels such collars may be drawing. Mr. Deacon, the former Borough Engineer of Liverpool, has, however, reduced traffic to a standard of tons per yard width of roadway per annum. This he effected by having the traffic in any street carefully watched for a certain definite time, the number of vehicles, their character and approximate weight being noted as well as the number of horses by which they were drawn, and their number of wheels.

The effect of the traffic thus tabulated, arranged, and reduced to ton yards per annum, can be ascertained upon any roadway, and Mr. Deacon has given the results of his observations in a valuable paper on the subject of street carriage pavements which he read before the Institution of Civil Engineers.[7]

Sir John MacNeill has estimated that 80 per cent. of the total wear of a road is due to traffic, the remaining 20 per cent. being due to atmospheric causes. Of this 80 per cent. 60 per cent. he considers is due to the action of horses’ hoofs where the traffic is fast, and 44·5 per cent. where the traffic is slow. General Morin estimates the wear of a road due to horses’ feet to be two-thirds of all causes. There can be no doubt that the action of horses’ feet, shod as they are with heavy iron shoes with long toe pieces and heels, must have a destructive effect upon the surface of a carriage-way, and this may be easily observed when watching the ruts formed by any continuous line of traffic in a roadway.

The following remarks from a report of the Society of Arts on this subject may here be of interest. “It may be mentioned that as respects the horses’ shoes, attention has long been called to its defects by Sir Francis Head and others, but Sir Joseph Whitworth now points out the achievement of a decided and important improvement, which will have a large effect in road conservancy, as well as the reduction of noise. The improvement consists in the fastening of a rim of hardened steel, of about half-an-inch square, to the horses’ feet, and letting the frog grow to its natural size. One effect is to reduce by five-sixths the weight of the old shoe, or in other words to reduce by five-sixths the weight of the iron hammers constituted by the common horses’ shoes, pounding the road surface, and creating road dust and dirt, and distributing it about. The saving in this respect, as well as the reduction of noise by the reduction of the weight of rim, and also the saving of road wear, would warrant the imposition of the stimulus of a tax, or a toll upon heavy horses’ shoes to hasten this removal.”[8]

Up to the present date, however (1883), no general change has been effected in the manner of shoeing horses, notwithstanding these admirable remarks of Sir Joseph Whitworth upon the subject.

With reference to the question of traction upon roads General Morin, in his ‘Expériences sur le Tirage des Voitures,’ states that the resistance to the rolling of vehicles upon solid metalled roads and pavements is proportional to the weight and inversely proportional to the diameter of the wheels. On solid roads he states that the resistance is nearly independent of the width of the tires when they exceed 3 or 4 inches, but on a compressible face it decreases in proportion to the width of the tire; the resistance further increases with the velocity on hard roads, but does not do so when they are soft.

The following table is almost universally now adopted as showing the traction upon level roads formed of different materials, asphalte being taken as the standard of excellence in this respect.

There are four forces constantly at work tending to destroy the momentum of vehicles passing along a roadway: they are gravity, collision, friction, and the resistance of the air.

The first of these is lessened by easy gradients in a road, the second can be overcome to a great extent by evenness of surface, the third by hardness, and the fourth, as well as all the others, by giving sufficient foothold to the animal drawing the vehicle.

Another excellent table[9] prepared from experiments made by Mr. Amos on different descriptions of pavement in the City of London may be useful, and is here given:—

The following table from Law’s ‘Rudimentary Treatise on Civil Engineering’ shows the force required to move a load of a ton weight on different descriptions of roadway, the limiting angle of resistance, and the greatest inclination which should be given to the road being also stated.

As a matter of fact, however, the gradient of a macadamised road should not, if possible, exceed 1 in 20,[10] experience having shown that a horse, unless the hill is a very long one, is able to draw his ordinary load for a level up such an inclination, whereas, if it is steeper he is sometimes stopped altogether, even though the carter tries the zigzag route so as to obtain an artificial ease of gradient.

The table given in ‘Molesworth’ upon the same subject is too well known to be repeated, and another table may be found in Sir Henry Parnell’s work on roads, which gives a comparison between the draught necessary on a well-paved road at 2, on a well-made, clean macadamised road at 5, whereas on a wet and muddy gravel or flint road it rises to 32!

Mr. T. D. Hope, of Liverpool, assuming the power of traction at 100, gives the following table:—

And Lieut. Crompton has given the resistance of wheels in lbs. per ton on different surfaces as follows:—

Here “newly-laid metal” comes out very badly, and points to the necessity of rolling, of which I shall speak in a future chapter.

Whilst on the question of wheel resistance, it may be well to note that the small front wheels of a waggon cause considerably more harm to a macadamised road than the larger hind wheels. In the smaller diameter any loose stone or obstruction is pushed along in front for a considerable distance, often tearing up the surface of the road, whereas in the other case the stone is forced into its place or crushed as under a roller.

On the question of “safety” to traffic, Mr. Haywood, the eminent Surveyor of the City of London, has caused several most complete observations to be made from time to time, the results of such observations being detailed by him in various reports. Amongst other useful information compiled by him, he has ascertained that a horse will travel 446 miles upon a roadway paved with blocks of wood without a fall, 191 miles upon asphalte, and 132 miles upon granite setts. I cannot do better than give verbatim his remarks upon this point:—

“Slight rain makes both asphalte and wood more slippery than they are at other times. On asphalte the slipperiness begins almost immediately the rain commences, wood requires more rain before its worst condition ensues. The slipperiness lasts longer upon wood, on account of its absorbent nature, than it does upon the asphalte; when dry weather comes after the rain, when asphalte is in its most slippery state, and the horses fall on it very suddenly, on wood their efforts to save themselves are more effectual; wood also is frequently in that peculiar condition of surface in which horses slip or glide along it without falling. A small quantity of dirt upon asphalte makes it very slippery, wood requires a large quantity. Slipperiness can be temporarily cured on both pavements; on the asphalte by sprinkling it with sand, on the wood by sprinkling it with gravel. The result in both cases is dirt. The sand thrown on asphalte helps to wear it out, the gravel thrown on wood tends to preserve it. When a horse falls on asphalte it has difficulty in getting up; on wood it rises more readily.”[11]

In streets crowded with traffic, the constant stopping and starting, especially on any surface that is slippery, is very trying to horses. Attention has lately been directed to this point with a view to the storage of some power in a vehicle, either by the compression of a spring in stopping or by some other mechanical means, in order that in starting the driver may at will liberate this power so as to assist the horse in overcoming the inertia of his load. These trials, however, have not at present met with much success.

Before closing this chapter on traffic, it will be well to point out that nearly all vehicles travelling rapidly can pass each other safely if allowed a clear space of eight feet; hence all roadways should, if possible, be made of a width between the kerbs of some multiple of eight: a convenient width for the footpaths, so far as foot-passenger traffic is concerned, is found to be one-fifth of the entire width of street. It is scarcely necessary to add that vehicles pass each other on the left side, pedestrians on the right. It is not easy to assign a cause for the former beyond custom, except that the whip is held in the right hand, and in consequence free play is given for its use as the driver sits on that side and can watch his wheels in passing. In France and other countries the right side is the “rule of the road.” In the case of pedestrians it is perhaps more convenient for many reasons to pass on the right side, one being that the umbrella or parasol is always carried in the right hand, which is also used to remove the hat when bowing, and another because one’s tendency in passing any obstacle is to give way with the left shoulder. For regulating the traffic and for the protection of foot passengers, “sanctuaries,” as they are termed, have often to be constructed by surveyors in broad streets or awkward centres of traffic, and it is well to place a lamp-post on these sanctuaries, on which may be advantageously fixed a notice, “Keep to the Left,” so as to regulate vehicular traffic. On the lamp-posts at the edge of the footpaths it is also sometimes customary to fix small enamelled iron plates bearing the inscription on both sides, “Keep to the Right,” so as to regulate the pedestrian traffic.

Of the danger to life and limb to pedestrians in London much has frequently been said, and no wonder, when we consider the number of persons who are daily injured and sometimes killed according to the Registrar-General’s returns. Some years ago it was proposed to erect light iron bridges over the most dangerous crossings approached by winding stairs, but “time is money” in the mighty metropolis, and the scheme was abandoned because it was felt that most persons would prefer the risk of being run over rather than spend the time in ascending and descending the necessary steps for this purpose.

CHAPTER V.
MACADAMISED ROADWAYS.

I do not propose in this work to speak of any of the engineering operations necessary to lay out or construct long lines of connecting roadways, as that is a duty which seldom falls to a town surveyor to perform, and there are a great number of treatises and books upon the subject already published. The object of this chapter will be to give some information and hints upon the construction and maintenance of what are known as macadamised roads, suitable for urban and suburban traffic.

There can be little doubt that roadways of this description are expensive luxuries where the cost of their maintenance, owing to excessive traffic or other causes, exceeds 2s. per square yard per annum, but they are often necessary luxuries when the requirements of the locality are considered, a point to which I drew attention in the preceding chapter upon “Traffic.” For purposes of what may be styled “pleasure traffic,” macadamised roadways are unequalled when well constructed and maintained, but there are many objections to them which will be considered in their place in this chapter.

The word macadamised is, as is well known, derived from one John Loudon Macadam, who in the year 1816 first took up the question of putting broken metal upon a road instead of the boulders previously used.[12] His name, being rather a peculiar one, has been attached to this description of road ever since.

As a matter of fact, the “macadamised” roadways of the present day are constructed after a method introduced by Thomas Telford as an improvement upon Macadam’s principles, and a perusal of the two following specifications will, I think, show that there is not very much difference between the method introduced by Telford and that followed at the present time.

Specification of a Roadway as designed by Thomas Telford more than fifty years ago.[13]

“Upon the level bed prepared for the road materials, a bottom course or layer of stones is to be set by hand in form of a close, firm pavement; the stones set in the middle of the road are to be seven inches in depth; at nine feet from the centre five inches; at twelve feet from the centre four inches; and at fifteen feet three inches. They are to be set on their broadest edges lengthwise across the road, and the breadth of the upper edge is not to exceed four inches in any case. All the irregularities of the upper part of the said pavement are to be broken off by the hammer, and all the interstices to be filled with stone chips firmly wedged or packed by hand with a light hammer, so that when the whole pavement is finished there shall be a convexity of four inches in the breadth of fifteen feet from the centre.[14]

“The middle eighteen feet of pavement is to be coated with hard stones to the depth of six inches. Four of these six inches to be first put on and worked in by carriages and horses; care being taken to rake in the ruts until the surface becomes firm and consolidated, after which the remaining two inches are to be put on.

“The whole of this stone is to be broken into pieces, as nearly cubical as possible, so that the largest piece in its longest dimensions may pass through a ring of two and a half inches inside diameter.

“The paved spaces on each side of the eighteen middle feet are to be coated with broken stones or well-cleaned stony gravel up to the foot path or other boundary of the road, so as to make the whole convexity of the road six inches from the centre to the sides of it, and the whole of the materials are to be covered with a binding of an inch and a half of good gravel free from clay or earth.”

If the above specification, written more than fifty years ago, is compared with one of the present date, it will be seen that there is a strong resemblance between them.

Specification of a Roadway as now executed.

The cross section of the roadway when finished is to be an arc of a circle, with a rise of 1 in 27 from kerb to the centre of the roadway each way.[15] The roadway, when consolidated and finished, to be 12 inches in depth at the gutters and 15 inches at the centre, diminishing gradually from this point right and left to the depth named. The gutters to be 2 feet in width, formed of stone setts 6 inches by 6 inches, and laid in sand, on a firmly consolidated surface of small broken stone or gravel.

The earth road-bed on which the surface formation is to rest is to be excavated to the required depth, and when graded and shaped to its proper form, it is to be thoroughly and repeatedly rolled with a steam roller, and all depressions which then appear are to be filled with the same material as the road-bed, and rolled until the whole be uniformly compact and firm.

On the road-bed thus formed and compacted, a bottom layer of stone of a depth of 8 inches at the centre of the road, and gradually diminishing to 6 inches at the kerb, is to be set by hand, to form a close, firm pavement. The stones are to be laid, with their largest side down, in parallel lines across the street, breaking joint as much as practicable.[16] The width of the upper part of the stone not to be more than 8 inches, nor less than 6 inches. The stone not to exceed 15 inches in length. After being set closely together, the stones are to be firmly wedged by inserting a bar in all possible places, and placing between them stones as nearly as possible of the depth of the pavement, until the whole is bound in position. Projections of the upper part of this course are to be broken off, care being taken not to loosen the pavement; and no wedging is to be done within 20 feet of the face of the work being laid. The small interstices are to be filled in with stone chips firmly wedged with hammers. The whole is to be thoroughly rammed and settled to place, and all undue irregularities of surface broken off.

On the foundation course must be laid an intermediate layer of broken stones, varying in size from 3 inches in their greatest diameters to 1 inch in their smallest diameters. These irregular-sized stones may be either the “tailings” of the screened stones, or may be raked from the quarry, and placed on the roadway without being machine-broken; but they must nevertheless be so laid as to compact solidly, and must be clean broken stone, free from dust and dirt, and within the dimensions given above. This intermediate course must be 4 inches in depth at the centre of the roadway, gradually decreasing to 3 inches in depth at the gutters; it is to be thoroughly rolled with the steam roller until it be firm, compact, and solid. On its upper surface it must be identical in rise and form to the cross-section of the finished pavement, as specified above. In the laying of this course of stone a small quantity of binding material is to be used, sufficient only to fill up the crevices, and render this portion of the pavement solid. Preferably the binding is to be of fine screened gravel or sand, which is to be sufficiently watered during the process of rolling, so that the “licking up” of the road material, and its adherence to the rolling-wheels may be prevented.

On the intermediate course is to be laid the surface layer of broken stone.[17] It must be 2¹⁄₂ inches in depth, and the stones must be practically uniform in quality, and as near an approach to a cube in form as possible. Each stone used in this layer must have passed through a 2¹⁄₂-inch circular hole, and all stones that are wedge-shaped, and do not approach uniformity of measurement on their sides, are to be taken from the road with properly shaped rakes, and no stones allowed to remain which are not sound, strong, and equable in size and quality of material. The stones are to be raked into an even layer, and the steam roller passed over them twice or thrice. After this a quantity of fine screened gravel or sand is to be thrown on and sufficiently sprinkled to moisten the mass without “licking up.” The rolling is then to be continued (working the roller backwards and forwards, gradually from the gutter to the crown), with an occasional light watering of the pavement, until the cross-section be exact according to specification, the interstices filled in, the roadway firmly compacted and solid, and all excess of binding removed from the surface of the finished pavement.[18]

Telford’s object was the complete separation of the road metal from the subsoil by a firm and regular foundation, and this system has ever since held its ground. The advantages to be gained in constructing a roadway in this manner may be summed up as follows:—

(1.) Economy of construction, as a considerable quantity of metalling is saved; only 3 inches of properly broken stone and a little binding material being necessary, the foundation of the roadway (which really carries the traffic) may be made of a quality of stone unsuitable for road metal, or even of bricks or stones from old buildings that are being pulled down.

(2.) The prevention of the rising up or “spewing” of the clay or other soft material on which the roadway rests.

(3.) A solid foundation is secured which will successfully resist the weight and percussion of the traffic.

(4.) The increased facility for the drainage of the roadway water being ruinous to it.[19]

Instead of forming a paved or “pinned” foundation for macadamised roadways, sometimes what is called “hard core” is placed at the bottom of the road upon the surface formation.

This “hard core” is made of very heterogenous materials, often the waste products of the house refuse depôt, and consists of ashes, old pots and pans, meat tins, old bottles, shells, and a variety of similar articles; sometimes the core is made of burnt ballast, but in no case does it make so good a foundation as stones set by hand.

Concrete has also been employed as a foundation with great success, but it is very expensive, and is seldom used except under streets paved with either granite, wood, or asphalte, of which I shall speak hereafter; for if the traffic was so great as to necessitate the use of concrete for a foundation it would surely be better to give the roadway a more durable surface than macadam.

The following tables, showing the thickness of the foundation and metalling of broken stone roads, is from a paper on roadways, read to the Association of Municipal and Sanitary Engineers, by Mr. James Hall, Borough Surveyor of Stockton, and may be of use to those who would like to know what proportions to use.

Chalk has sometimes been used for the bottom of a roadway, but where this is likely to be affected by frost it is the worst material that can be used, as it is likely to blow up the roadway.

With regard to the annual outlay upon macadamised roadways, the following comparative tables[20] prepared by Mr. Ellice Clark, the then Surveyor of Derby, may be of interest.

The following is a table of the cost of streets in Paris per square yard per annum.[21]

The cost of maintaining macadamised roadways as compared with that of granite setts has been said to be as high as 5 to 1 and that this cost if capitalised for 12 or 13 years will equal the first expense, interest on money, and the necessary repairs for a granite paved roadway.

The following table gives the cost per annum per square yard for the maintenance of macadamised roadways in different places, so far as I have been able to collect them:

In Birmingham the macadamised streets have worn down 6 inches in one year, with a traffic of 2484 vehicles passing in 10 hours.

With reference to the great cost of maintenance in Paris, the following particulars[22] may here be given;

“The surface of the street is picked by gangs of men, metal from 2¹⁄₂ to 9 inches in thickness is then laid on, a coating of sand is then spread upon it, it is watered and rolled at per kilometre ton, that is, at per ton weight of roller per kilometre travelled, at a cost of about 15·33d. per ton mile for the first 250,000 ton miles, and at reduced rates for additional service. The materials used for the roads are flints costing 4s. 6¹⁄₂d. per cubic yard for light traffic roads; for medium traffic, hard millstone at 11s. 4d.; and for the heaviest and greatest traffic, porphyry at 15s. 9d. The average total cost of maintenance of the streets is 1s. 8¹⁄₂d. per square yard per annum for the first-class roads, and 1s. 1¹⁄₂d. for the lighter traffic; the highest cost for maintenance is as high as 10s. 9d. per square yard, the lowest 9¹⁄₄d. per annum.”

It may be well to mention that 73 per cent. of the streets in Paris are paved, 5 per cent. are coated with asphalte, and 22 per cent. are macadamised.

The contour, or best form of cross section that should be given to a roadway, has often exercised the minds of engineers, but for all practical purposes evenness of surface and regularity of section in a macadamised roadway are of more importance than the slight difference between straight lines and curves, which might only tend to confuse the workmen. Formerly it was the practice to employ a complicated gauge in the form of a straight-edge fitted with plummet or level and sliding bars, but a good eye, assisted by a long straight-edge and spirit-level and three boning rods, is generally found to be sufficient, and if the centre of the roadway is kept level with the heel of the footpath, a sightly cross-section is generally the result; or say 6 inches to 9 inches higher in centre of a roadway 30 feet in width between the kerbs, 3 inches to 4 inches where it is from 18 to 20 feet in width.

The following detailed section of a macadamised roadway is one which I am in the habit of specifying for suburban districts, as it is easily set out and constructed, and answers all purposes most admirably.