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various sizes. Of these the broken granite and granite cubesare most useful, the one for general purposes, the other forroads which are subject to great wear and tear, such as thosein the principal thoroughfares of London , for although bothdescriptions of material are used for this purpose, yet we areinclined to think that the broken stone is scarcely durableenough for such work ; and there is this further objection toit, that it is constantly requiring repairs, which must, to acertain extent, inconvenience public business. Besidesthis, as usually managed, they occasion a great deal of dustand dirt, while the draught of vehicles upon them is veryheavy, and their maintenance expensive. It would be scarcelyfair, however, to attribute the faults of management to thequality of the material, and we believe that many of the aboveobjections may be removed by skilful management.

In the first place, as regards durability, the objection wouldbe removed to a considerable extent by employing a goodfoundation, and laying the metal carefully upon it, providingfor the proper drainage of surface and substratum as men-tioned above, for the lodgment of water either above or belowsuch roads is very injurious, and tends, perhaps more thananything else, to their destruction. Having obtained a goodfoundation, the next point is to cover it with a hard compactcrust impervious to water, and laid to a proper cross section,so that it may be speedily drained and no water be allowed toremain on the surface, which, besides its inconvenience topassengers, is very destructive to the surface of the road.A practice has come into vogue of late, of covering theroad when made, with a binding composed of the grit col-lected off the road in wet weather, and by the operation ofwater-sweeping. The binding is laid on regularly andwatered until the new material is firmly set, which it doesvery quickly, and when the binding is of good quality andproperly laid on, it assists its formation very considerably,and altogether improves the condition of the road and econo-mizes the material, for it saves the wear and attrition of thenew stone. Some road-makers object to this binding on theground, that it destroys or rots the road, and that whenthe road is set it has to be carted away again ; but this isonly the case where improper binding is used, such as isswept from streets which are not properly cleansed, and there-fore consists principally of mud, and not of grit, or rather ofgrit so mixed with dirt as to be for the most part useless forbinding. This method of binding a road removes in partthe objection which is made against the resistance occasionedby the loose stones of a newly-laid broken road.

We alluded just now to the cleansing of roads, and it is amatter which deserves considerable attention, and is appli-cable to every variety of road; a dirty road is a constantsource, not only of inconvenience, but of expense, forscarcely any thing destroys a road more readily than dirt.And not only is this the case, but the tractive power alsorequired on a dirty road is twice as great as that required ona clean one : when we come to add to this the damage doneto property by the mud in wet weather, and the dust in dry,we shall be able to form some notion of the waste occasionedby dirty roads.

The best method of cleansing roads is by water-sweeping ;a method of watering and sweeping combined, the roads beingfirst watered and then swept, by which means the road isthoroughly washed from its impurities. The wateringis usually carried on by means of a water-cart, but a moreI effectual means, as far as the cleansing of the road is con-| cerned, is afforded by the hose and jet. The sweeping is| mostly effected by hand, and in some places this method is| carried on systematically, which is an improvement upon theI old practice ; but of all methods offered to the public, that of

Whitworth’s sweeping-machine, is the most effecb ve ^ a( ,))iiisthe end, we believe, the most economical. By ^ llS ^ tl> 6an endless chain of brooms is made to revolve g( jj a telymotion of the wheels, and to sweep the dirt iaxrafrom the roads up an inclined plane into the carb wl>' c 5fear of splashing, or any other annoyance to the pis a vast improvement on the old practice of stackm 0 in’ 1or dust up in heaps, and letting it remain in that s p 0 r'the carts come round, during which period a conside ^ oftion of it had probably been spattered about byblown in all directions by the wind, and even then p j lJVV liickmust expect to be bespattered by the negligentmanner otl’ efthe refuse was carted away. This machine, too, P re f. rjn pi'e 3 'advantages, in the width of the brooms, and thesure exerted throughout, a pressure which can also b “ j 3|as occasion demands. Water-sweeping by this ,naC me tho^ 0venture to assert, one of the best, if not the best, ^ ha*

cleansing roads, and our assertion is supported by la Ljof*** 8been objected that water-sweeping removes the m» jlr-

road, but the contrary has been proved to be the c (( j jiii' ,eSmith, the eminent surveyor of Birmingham , say®<^ p(°? e \found that the use of sweeping-machines,employment of water, has reduced the amount one -tl> ir 'jrequired for the repair of roads in Birmingham n t\ifl eAviz., from 20,000 to 13,000 cubic yards ; the ; D trod aC ,"iamount is the average of seven years preceding t se que at 'tion of the machines, the latter of the three years su re m»a.On the 22nd of March, 1848, some experiments ro»

upon the subject in the Quadrant, Regent-stree \t^

being then covered with a thick coating of dus > roa <j, b u ^causing great annoyance as well as injury to ^ a j s0could not be removed by scraping without removi ° ^jnedof the new stone to which it adhered. It was e T b

sweep half of it dry, and half after proper w ° j ie j ( °to se P (]ewas done, and the sweepings removed were wa - t h it! 0rate the refuse from the stony matter mixed coa rse $>third part of that which was taken dry consisted t^gjfth pawhich would have been useful on the road , ° n iva s st °only of that which was removed in the

form of ** be *

lOf'

matter, and that was so completely pulverize ^ tvV o P' ^scarcely any use—it had done its work. .^.gneotions of the road had been cleansed, the ^'® eI ve pt di'f t |, ethem was very striking. That which r a »oaether th«

still covered with adhesive matter, winch, t ^ wh ee ^j Jti dstones to which it adhered, was lifted by ^Jiieb ^whole road being rough and uneven. The po g|n0 otb> ^been swept with water was perfectly even an q uart l e ptthe 24th both portions were swept, but oni y wa ter- s e3

much dirt was taken from that which had e t hresas from the other. On the 26th it rained, a j w bi c 1 ^ e -as much slop was taken off the part of g^peri 03 ® 0 ,, b 1

not been water-swept on the 22nd. Thiscidedly proved the preservative effect of vva ver> tb emachine.—Notwithstanding these results, no jii

chine is now scarcely ever used. mu'*—

The granite-cube roads are preferable 0

-. - • - — more e»o „

in

vert'

point of durability, and therefore are but nc 'jyfln'

respect for places where there is great tia ^ t | ]eS e a ^piless there are objections which partlyoutweie, a ris e ® ve rftages, one of which, of considerable 3ffl ? M e * 1 i c le3 b e '°? 0 lefi cethe circumstance of the wear and tear ot ve . a nd '

on account of the frequent d , .»,

^ ieneraU? sP^bV

the draught upon macadamized roads is, ® an tag e33 ^b

heavier than upon pavement, yet this to>' v ^ u ickV

more than neutralized by the concussions Craveda great impediment and injury to vehicle

great on such roadsof the concussions to which they are