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strong prejudice against paved roads; but these prejudices have been created by the total want of skill in paving the streets of London, and their present very imperfect state. But if the middle sixteen feet in breadth of the present road were made use of as a foundation for a well-constructed pavement of stones of a moderate size, and of a cubical shape, with square joints, no road would be fitter for heavily-loaded carriages: the rough faces of the stones give a degree of action to the springs that eases the draft, while the perfect hardness permits carriages to move forward with a slight exertion by the horses. Along each side of the middle part there may be a roadway, twelve feet in width, made with broken stones of a durable quality. These side roads would answer for the lighter description of carriages and riding-horses. The whole breadth of the road, exclusive of footpaths, would, according to this plan, be forty feet. This appears to combine all the requisites for roads in the vicinity of a great city." (See Plate III. Fig. 2.)
A ROAD WITH A FOUNDATION OF PAVEMENT AND A SURFACE OF BROKEN STONES.
The following specification of the manner of constructing a road of this kind of thirty feet in
got the management of this road, they began to remove the pavement, and to substitute broken stones for it; and thus, without being conscious of it, they have destroyed the most perfect piece of turnpike road in England.
width, is taken from a contract for making a part of the Holyhead Road: —
"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 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.
"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 inches and a half inside diameter. The paved spaces on each side of the eighteen middle feet are to be coated with broken stones, or well-cleansed strong gravel, up to the footpath 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 in depth of good gravel, free from clay or earth." (See Plate III. Fig. 3.)
The work of setting the paving-stones must be executed with the greatest care, and strictly according to the foregoing directions: when the work is properly executed, no stone can move.
If the work is executed by contract, the inspector should see all the operations as they are going on. He should walk over the pavement when it is completed, and try whether the stones are firmly fixed; and he should not allow any broken stones to be laid on over the pavement till it has undergone an examination of this kind.
In breaking stones, the workmen should be required to break them as nearly cubical as possible. When this rule is not attended to, a great quantity of materials is wasted by first splitting the stones into thin slices, and then breaking them into pieces that are too small, and too thin. If the stones or top metal are not broken very small, the proper degree of smoothness of surface will not be obtained.
When stones are very hard, they never make a very smooth surface. Limestone will make a much smoother surface than whinstone and other harder stones, but they should not for this reason be preferred to harder stones; for these will wear longest, carriages will run lighter over them, and the expense for scraping and repairing will be less. All the soft kinds of stones make heavy roads in wet weather; and in dry weather there will be more friction upon roads made with them, because there will be more dust on their surface.
The breadth of the road which has been described in the foregoing specification of thirty feet, is recommended as fully sufficient for any road, except a road forming the approach to a very populous city. The confining of a road to this breadth contributes very much to preserve the whole surface of it, from side to side, in a good state, and to diminish expense. For when a road is of greater breadth, the scraping and repairing of the excess beyond thirty feet costs annually a considerable sum. Mr. Telford says, on this point, in his second annual report on the Holyhead Road, dated 17th June 1825 :—" He" (the surveyor of the Stonebridge and Birmingham Road) "seems to be still too much disposed to prefer a road of a greater breadth than that recommended by me, of thirty feet: he should reflect, that every yard in breadth makes 1,760 superficial yards to be kept in good order in a mile, and therefore that a road of thirty-nine feet wide has 5,280 superficial yards to be coated with materials, and kept clean, more than a road of thirty feet wide. The additional expense of the wider road may be set down at 15/. a mile, and this rate for ten miles will make on his road an extra expenditure of 150/. a year." ■
With respect to the convexity of a road, it should be so arranged that it should be slight in the middle. In giving a convexity of six inches to a road of thirty feet in breadth, the convexity at four feet from the centre should be half an inch; at nine feet, two inches; and at fifteen feet, six inches. This will give the form of a flat ellipsis.
The binding, which in the foregoing specification is required to be laid on a new made road, is by no means of use to the road, but, on the contrary, injurious to it. It is, however, unavoidable when a long piece of new road is to be opened; for, without it, the wheels, by sinking into the new materials, would make the draught of the carriages much too heavy for the horses. This binding, by sinking between the stones, diminishes the absolute solidity of the surface of the road, lets in water and frost, and contributes to prevent the complete consolidation of the mass of broken stones.
If the plan here laid down for constructing a road be faithfully executed, it will secure all the objects that can be required. From the moment it is first opened, it becomes daily harder and smoother, and very soon consolidates into as hard a mass as can be obtained by the use of broken stones. The subsoil of the road cannot get into a state of puddle, and rise up and mix with the surface materials, and thus produce those quagmires and deep ruts that are met with every winter on roads made in the usual way.
Although the expense of constructing a road on this plan may seem to be great, on an average of five years, the joint expense of constructing and repairing such a road will be much less than that