1U 



IIOADSTKAD. 



196 



*t the inU-nwctioo of dreeta. u it diminishes the ruk of horses slipping. 

 LosMitudinal courses are objectionable on account of the tendency of 

 narrow wheel* to enter the joinU In paring cteep inclinations, it U 

 nil to UM narrow stones, oil account of the number of crow-joint* ; 

 i. if Urge U>ne be used, to out deep furrow* across their surface, to 

 aflbH secure footing. A plan of paving for tuch situation*, which baa 

 very effectual, 



been found wry i 



'|SMBM v |MB**WQ * 



U represented in the annexed dingr 



which the (tones are so inclined as to present a series of stops. The 

 fM* objection to this plan seems to be the jolting caused to carriage*, 

 which produces so deafening a noise that, in one instance, such a 

 pgTttnjat was taken up at the request of the inhabitants of the street. 

 Many patent* hare been procured for plans of forming stone pavements 

 in which the pressure of carriages might be simultaneously distributed 

 orer sereral stones, by various contrivances for dovetailing and other- 

 wise fitting the stones together ; but such plans are generally too com- 

 plicated, requiring an accuracy of formation that would be very 

 expensive, owing to the hardness of the stone. Thin blocks of stone, 

 bedded in aiphaltc, have been tried, and appear to make a good 

 pavement. 



When completed, a thin coat of gravel spread over the surface ia 

 useful in diminishing the effect of the jolting of carriages on the new 

 pavement. In case of taking up any part of a pavement to attend to 

 water-pipes, Ac., great care is necessary in relaying the part, in doing 

 which it ia well to apply some fresh broken stone to the bed, and 

 to lay the paving (tones without mortar, until the foundation ia 



The serious defects of the common stone pavements have led to a 

 variety of experiments on other methods of forming carriage-ways 

 suitable for streets, of which the adoption of broken stone, or mac- 

 adamised roads, has been the most general Opinions differ widely as 

 to the propriety of this measure, but an idea seems to be gaining 

 ground that the comparative quietness of such a road, and its superior 

 ease to passengers, are insufficient to counterbalance the increased 

 draught of carriages, the dust of summer, the mud rapidly formed in 

 wet weather, and the great expense of keeping in repair a metalled 

 road when subjected to the constant wear of a busy town. 



The enormous expense of maintaining some of the metalled roads 

 in London has led to attention being given to various plans of paving 

 with wood. A very coarse kind of wooden road, consisting of rough 

 logs laid close together across the track, is much used in North 

 America, under the name of corduroy roadt, but the wooden pavement, 

 properly so called, seems to have been first used in Russia, and tried on a 

 {united scale at Vienna, New York, and some other places, within a few 

 years. One of the earliest kinds used consists of blocks of fir or other 

 wood cut into hexagonal cylinders, of 6 or 8 inches diameter, and from 8 

 to 12 or 15 inches deep, and placed close together, with the grain verti- 

 cally. The blocks are sometimes tarred, or may be kyanised; but 

 even where no such precaution is used, the wear is very trifling, as the 

 swelling of the wood from moisture makes the joints very tight and 

 impervious to water. Such a pavement is very smooth when first laid, 

 but unless the foundation be very carefully prepared, it is liable to 

 idnk into hollows like the common stone pavement, owing to the want 

 of cohesion between the individual blocks, a deficiency which it has 

 been proposed to remedy by pegging or dowelling the pieces together, 

 though their form is not very suitable for the purpose. Some speci- 

 men* have been laid on a flooring of planks, to avoid this inconvenience. 

 Numerous other systems of wood pavements have been adopted, 

 but in spite of the incidental advantages (as in the case of the 

 suppression of noise, Ac.) they have been found to be so danger- 

 ous to hones as to render it necessary to abandon the use of that 

 tntril 



Another description of road that has lately attracted much attention 

 U that consisting of an asphaltic composition. Many attempts have 

 been made to form roads of gravel and other materials united by 

 animal oleaginous or gelatinous substances, or coal-tar, into a kind of 

 concrete ; but such attempts have seldom proved successful on a large 

 scale. Mineral substances of similar character have proved more 

 advantageous, and the native asphalt* procured near Seyssel, in the 

 department of l'Ain,and some other places, has been found to produce, 

 when mixed with a small portion of native bitumen, a substance 

 admirably adapted for the formation of smooth roads, and a variety of 

 other important purposes. It application to carriage-ways has been in 

 this country chiefly confined to court-yards, for which, as well as for 

 terraces and footpaths, it is very suitable. The asphaltic mastic of 

 Seyssel, as prepared for use, consists of ninety-three parti of native 

 anphalte reduced to powder, and seven parts of bitumen ; the two 

 being melted together, and a little fine gravel or sand stirred in with 



the mixture. The composition is ready for use when it simmers with 

 a consistency similar to that of treacle, and it is spread while hot so as 

 to furm a coating about an inch thick upon a levelled foundation of 

 i.iiicn to. The thickness of the asphalte is regulated by slips of wood 

 or iron, which .are often BO disi>o8ed as to divide the pavement into 

 ornamental compartments, the asphalte being made of various colours 

 by the admixture of different kinds of sand or other substances. 

 Where the ornamental character of the pavement forms a distinguish- 

 ing feature, beautiful imitations of mosaic work may be executed with 

 asphalte. The genuine natural asphalte possesses a degree of elasticity 

 that renders it exceedingly durable; but artificial compounds in 

 imitation of it generally require too much bitumen, and are injuriously 

 affected by great changes of temperature. Some experiments have 

 been made, but with very indifferent success, on the formation 

 of carriage-ways with large blocks of asphaltic composition 

 containing a considerable quantity of gravel or broken stone. 

 [ASPBU.TE.] 



Foot-pavements of flag-stones require very little remark. The curb- 

 stones should be very hard, and firmly set in cement on a bed of gravel. 

 They usually rise about 6 inches above the surface of the carriage-way, 

 which may be made to abut immediately upon them, without the 

 intervention of a gutter. Where gutters are introduced, those of cast- 

 iron are to be preferred. The flagstones, which should never be less 

 than 2} or 3 inches thick, are commonly bedded in mortar on a layer 

 of gravel ; but sometimes, when there are no cellars underneath, are 

 laid dry. The appearance of many of the new streets of London in 

 greatly improved by the use of flagstones of extraordinary dimensions, 

 extending the whole width of the pavement; and a similar appearance 

 at much less cost may be obtained by the use of asphalte. A slight 

 degree of slope should be given to the pavement, to conduct water to 

 the gutters, for which purpose a fall of 1 inch in 10 feet is sufficient, 

 while a steeper inclination is objectionable from its danger in slippery 

 weather. 



Among the substitutes for common Yorkshire flagstones that have 

 been recommended, may be mentioned slate, which appears to be very 

 durable. Some pavements or floors of this material have been laid at 

 the London Docks, where, among other advantages, it is found pre- 

 ferable to wood in point of cleanliness. Trackways of slate 2 inches 

 thick are found strong enough to bear waggons or carts with 4 or 5 

 tons of goods ; and some are laid of only half that thickness on an old 

 wooden floor. 



A ' Treatise on Roods,' &c., by Sir Henry Parnell, of which a second 

 edition was published in 1838, may be consulted with advantage by 

 those desirous of obtaining further information on the theory and 

 practice of rood-making. The works of Bergeir, McAdarn, Edgeworth, 

 Sganziu, Schwilgud, Lehay, and several others; and the various 

 Parliamentary Reports relating to roads from the commencement of 

 the present century, as well as those of the Holyhead Road Com- 

 missioners, also contain much valuable matter on this subject. It 

 may be interesting to add, as a means of forming an approximate idea 

 of the importance of our ordinary roads, that the sum laid out in the 

 repairs of the turnpike roads of England and Wales in 1857 was not 

 less than 1,127,791'., including the interest on the debt, or a sum of 

 182,03#. ; and that the county roads cost 2,286,559i There ore no 

 recent returns of the lengths of the different kinds of roadways, but 

 the cost of maintaining a turnpike road may be taken at 501. per mile, 

 and that of county roads at 111. per mile. 



ROADSTEAD, a sheltered bay, or portion of a sea-coast, in which 

 vessels may lie safely at anchor until the tide should allow of their 

 entering the harbour or dock at the bottom of the boy, or to pass the 

 bar of a river discharging into the some. There ore other roadsteads 

 upon open coasts, formed by reefs or sand-banks running parallel to, 

 but at some distance from, the shore, which afford shelter from 

 winds blowing in certain directions, and thus materially assist 

 the coasting- trade. Portland Hoods and Spithead are illustrations 

 of the first class of roadsteads; Yarmouth and Deal Roads are 

 of the latter class. Plymouth, Cherbourg, and Delaware Bay have 

 been artificially converted into safe roadsteads, and the same 

 result has been attained by the remarkable works executed at the 

 Helder. 



The essential conditions of a safe roadstead are, that it should pre- 

 sent a large area of water-surface of great depth ; that it should have 

 good holding ground ; and that it should be protected from all winds 

 which are likely to create much agitation in the water. The entrance 

 must be easy, and indeed it is preferable that there should be more 

 than one entrance to a roadstead, so that a vessel driven by stress of 

 weather may be able to make either the one or the other pass, or, if 

 driven past one of them, may still have a chance of taking refuge in 

 the other. It is precisely for this reason that the roadstead of the port 

 of V'igo is one of the most admirable harbours of refuge in Europe ; 

 for the Islas da Bayona stretch across the mouth of the bay, leaving 

 two channels near the shores of the main land, and an overlapped 

 channel between the two islands. The artificial roadsteads at Ply- 

 mouth and Cherbourg have two navigable passes, for the breakwaters 

 are in both cases formed in deep water, and without connection with 

 the shore ; but neither of these marvellous triumphs of human inge- 

 nuity and perseverance are so efficient as is the natural screen at Vigo 

 in checking the transmission of the external agitation. lu the open 



