133 



ROAD. 



Dwtription of Stone. 

 GaernMj . 

 Ilerm* . 

 Ludlet 



Blue Peterheod 

 llcjton 



Bed Aberdeen . 

 D&runoor 

 Bio* Aberdeen 



Loss of Depth. 

 Absolute. Comparative. 



OGO in. 

 075 

 062 

 131 

 141 

 159 

 207 

 125 



1-000 in. 



1-190 



1-316 



1-080 



2-J38 



1-524 



3-385 



3-571 





Stone tramway* have been adopted in many street pavements where 

 a great traffic is carried on, particularly in some of the narrow streets 

 in the city of London, with much advantage ; but their application to 

 acclivities on ordinary road* ha* hitherto been more limited than their 

 menu deserve. By their judicious introduction on a few steep incli- 

 nations, many hilly roads might, at a small expense, be made nearly 

 equal to level lines ; and it is probable that such a measure would tend, 

 in an important degree, to enable turnpike-roads to meet die for- 

 midable rivalry of railways. In his report to the Holyhead-road 

 Commissioners in 1839, Mr. Macneill strongly recommends the applica- 

 tion of stone or iron tracks to several hills, and states that an iron 

 tramway laid down along the whole length of the road would reduce the 

 expense of hone labour fully one half. " If," he writes, " a tramway 

 were constructed of iron plates, the whole way from London to Bir- 

 mingham, a coach carrying sixteen paaaengers might be drawn at the 

 rate of ten mile* an hour with only two hones, and one hone would 

 be able to draw a post-chaise more easily than two now can, so that 

 the expense of travelling might be reduced one half, and a similar 

 reduction might be made in the charges) for carrying goods. The 

 expense of forming such a railway would be about 2SOOJ. a mile, 

 making the whole expense from London to Birmingham 371,0001." In 

 addition to the immediate advantage* of such an improvement, it would 

 remove one of the greatest obstacle* to the successful use at steam 

 locomotives on common roads. 



Part*M*ti.Th formation of pared roads on correct principles 

 appears to hare been well-understood by the Romans, whose pavement* 

 how great care in their untlil feature., a good foundation and 

 accurate fitting of the stones. Son* of the modem imitations of the 

 Roman system in the street-pareroenU of Italy show the like attention 

 to these important points, the paving-stones being set in mortar on a 

 concrete foundation with a degree of accuracy that has led some 

 writers to designate these roads horizontal mlU. In some instances 

 the blocks of stone used are of considerable depth ; but they are often 

 thin, and, being of large dimension*, hare more the character of 

 flag-stone* than of ordinary paving blocks. At Naples sod Florence, 

 toon 2 feet square and inches thick, laid diagonally acrots the road, 

 and neatly set in Poaraolano mortar, are used; the surfaces being 

 chipped where declivities or turnings occur, to prevent the slipping of 

 hones, which become very sure-footed from habit Occasionally, as at 

 Milan, different kinds of paring are hud for the wheel-tracks and bone- 

 path, so as to produce the effect of a stone tramway. These pave 

 meats hare been recommended as models for imitation in paring the 

 streets of London ; but the durability with which they are constructed 

 would form a disadvantage in a place where the pavement has to be 

 frequently disturbed for the purpose of laying down or repairing water 

 and gas- pipes, or cleansing the sewen ; and it is probable that pare- 

 menta which answer well for the light vehicles and limited traffic of 

 many of the continental cities, would be found quite inadequate to 

 bear the number nf heavy carriages inverting the principal thorough- 

 fares of the metropolis ; of which some idea may be formed from the 

 fact that from six o'clock, A.M., of March 18, to six o'clock, A.M., 

 March 17, 18S0, there were observed to pans over London Bridge, 

 448* cabs, 4286 omnibuses,; 245 waggons and cart*, and 2430 other 

 vehicle., or 20,444 in all. 



Another description of pared road, the origin of which is commonly 

 referred to the Romans, in the e*am*e>, or roughly-pared causeway 

 need in the principal highways of France and some other parts of the 

 i-nt. This kind of 'road has been much recommended for its 

 <lun>l,ility when well made, but, unless laid with a degree of care that 

 rcn'ler it too expensive for general adoption, it causes a very 

 unpleasant and fatiguing jolting. In such roads the pavement usually 

 covers only a part of the breadth of the road, leaving the sides avail- 

 able for the use of the light carriages in dry weather; and it has been 

 suggested, that where the width of the roadway would allow, it might 

 prove advantageous to form, in all great roads, a track of pavement or 

 hard broken stone for winter use, and another of inferior material* 

 urner, both to save the wear of the hard road and increase the 

 rt of passenger*. Such an arrangement is convenient in the 

 al approaches to great towns, where it is considered best to 

 have the pavement atr the sides, that carters may walk either on or 

 near the footpaths, and that foot-paawngen mar not be incommoded 

 by the dirt of the metalled road. 



In Holland, pavement* of brick, which are also probably derived 

 from the practice of Roman engineers, are extensively used, not only 

 for footpaths, but also for the passage of heavy carriages, which run on 



Hen U aa Islaad tdjohuaf Goenuev. 



t A wbiastPM (T*B XortaanWrUnd. All tat rest ttt panlu*. 



ROAD. 134 



them with great facility. The bricks used for this purpose are thin, 

 and well bedded in lime. 



Common stone pavements are, by most writers, divided into two 

 classes : rwtife causeway, in which the stones are of irregular shape, 

 and very imperfectly dressed with the hammer ; and dratted causeway, 

 which is formed of stones of larger size accurately squared and dressed. 

 In both kinds the excellence of the pavement depends greatly on the 

 firmness and evenness of the bed, and the caref id fitting of the stones 

 to each other, which may be accomplished with very irregular stories 

 by judicious selection. If one stone be left a little higher or lower 

 than those adjoining it, or if it become so in consequence of defective 

 bedding, the jolting of carriages in passing over the defective place will 

 quickly damage the pavement ; the wheels acting like a rammer in 

 driving the depressed stones deeper into the earth, while the derange- 

 ment of the lateral support that each stone should receive from those 

 adjoining it, occasions the dislocation of the pavement to a consider- 

 able distance, and the consequent working up of the earth through the 

 disturbed joints. Defective joints form another fruitful source of 

 injury and inconvenience both to the pavement itself and to the vehicles 

 jolted over it. If, as is often the case in inferior pavements, the edges 

 of two adjoining stones do not meet with accuracy, narrow wheels will 

 have a tendency to slip into the joint, and by doing so, to wear the 

 edges of the stones, till, as may be frequently seen, the surface of each 

 stone is worn into a convex form that renders the footing of horses 

 insecure, and causes the motion of vehicles drawn rapidly over them 

 to consist of a series of bounds or leaps from one stone to another, 

 accompanied by a degree of lateral slipping highly injurious to the 

 carriage, while the irregular percussion produced tends greatly to the 

 destruction of the pavement. 



In order to procure a firm foundation, and to prevent earth from 

 working up between the stones, it is advisable in the first instance to 

 form a good carriage-way of gravel or broken stone, and to allow it to 

 be used by carriages till consolidated, before laying the pavement. 

 This plan is stated by Edgeworth, in his ' Essay on the Construction 

 of Roads and Carriages,' 1817, to have been practised successfully by 

 Major Taylor, of the Paving Board, in some pavements in Dublin, and 

 it is strongly advocated by more recent road-makers. Where broken 

 stone is laid to a considerable depth, it should, as in the case of 

 metalled roads, be applied in thin layers, each being separately worked 

 into a compact state. In streets of very great traffic, it is a good plan 

 to lay a sub-pavement of old or inferior stones, bedded on broken 

 stone, as a foundation for the surface pavement, a measure which has 

 beam practised with advantage in Paris ; but of late years it has been 

 the custom in London to form the bed of paved roads by means of a 

 layer of gravel, perfectly clean, which in rudely converted into a species 

 of concrete by floating the surface with lime-water. The bed of 

 the pavement should be formed into a slight convexity, the slopes 

 being about 2 inches in 10 feet. A thin coat of gravel or sand laid 

 immediately under the paving blocks is of use iu filling up slight 

 irregularities in their shape, and enabling them to form a com- 

 pact bed. 



For the paring stones hard rectangular blocks of granite arc pre- 

 ferred, though whuutone, limestone, and even freestone, may be used. 

 Guernsey granite, as shown by the table in a previous column, appears 

 to be the most durable, but it is more liable to become inconveniently 

 smooth than some stones of inferior hardness, such as the Mount 

 Sorrel or Aberdeen granite. The stone* may vary, according to the 

 tnffic, from 6 to 10 inches deep.C to 18 inches long, and 4 to 18 inches 

 wide; but it is very essential that the depth of all the blocks iu DIM- 

 piece of pavement should be alike, and that where the width is unequal, 

 the stone* be so sorted that all used in one course should be unifunu 

 in this particular. The accurate dressing of the stones is a point often 

 too little attended to ; and an injudicious mode of forming contracts 

 for paving, in which the payment has been by the square yard of 

 paving laid, has, in connection with the effect of competition in bring- 

 ing prices below the remunerating point, led to the use of stones in 

 which the base is smaller than the upper surface, and which, when laid, 

 scarcely come in contact with each other except at their upper edges. 

 In some pavements the stones are made smaller at the top than the 

 bottom, the joints being filled up with stone-chips, concrete, or an 

 asphaltic composition ; and in those of the more common construction 

 the Milei of the stones are occasionally hollowed, so as to receive a 

 small quantity of gravel or mortar, which serves as a kind of dowelling. 

 l'*mTnmg the stones with a heavy wooden hammer is a practice that 

 ha* been much recommended, and it is considered that a more efficient 

 application of the process, by means of a ramming-tnachine, or portaUc 

 minify, would remove some of the defects arising from imperfect 

 bedding ; hut when the stones are well laid, and bedded iu strong 

 mortar, as the best recent pavements are, a few blows with a wooden 

 maul of about 14 pounds weight are sufficient to fix them firmly in 

 their place. Grouting with lime-water poured all over the pavement 

 facilitates the binding of the whole together, and fills up the joints, 

 so as to effectually prevent the working up of the substratum. The 

 blocks are commonly laid in rows across the road, the joints in each 

 row being different from those of the adjoining ones ; but pavements 

 of superior smoothness have been laid in courses stretching diagonally 

 across the street, by which means all the joints are jwscd over by 

 carriagei with greater case. This arrangement is particularly desirable 



