Book II. REPAIRING ROADS. 545 



tliink that five hundred gig or one-horse chaise wheels, of four hundred weight each, in 

 all one hundred tons, would so completely destroy the cohesion of the stone, as the single 

 crush of the heavy wheel. Conceiving, therefore, that the destructive effect of pressure 

 on the roads increases, from tlie lowest weights to the highest, in a very rapidly increasing 

 ratio, I think that all reasonable ingenuity should be exercised, so as to construct our car- 

 riages as for each wheel to press the road with the least possible weight that the public 

 convenience will allovi'." 



3486. A arcat weight in one rolling mass (fig. 446. \ Fry continues, "has a tendency 



to disturb the entire bed of the road, whether it be on a six-inch wheel or on one of 

 sixteen inches, and whether on conical (Jig. 445 a) or on cylindrical wheels (Jig. 445 b). 

 Under all these considerations, I am satisfied that the only grand desideratum on behalf 

 both of the roads and the horses, is light pressure. And therefore any dependence 

 on breadth of wheels, as a security against the destructive effects of pressure, is in 

 my opinion fallacious. I wish here to be understood as applying these remarks upon a 

 supposition that wheels were made upon the most philosophical construction ; that is to 

 say, perfectly cylindrical (Jig. 445 b) ; and that they stood perfectly upright or vertical. 

 The present system of broad wheels I consider a system of mere mockery." 



3487. Fri/ proposes to attain his principle of the division of power by the adoption of 

 light one-horse waggons with six or eight wheels ; which in our opinion are of very qes- 

 tionable advantage, all things considered, compared to one-horse carts, to carry one ton, 

 and four-wheel waggons to carry four tons. One-horse waggons, he says, fully embrace 

 the principle ; and the labor of the horses would be much more efficiently applied than at 

 present. If light one-horse waggons were constructed, to weigh eight hundred weight 

 each, and these were charged with a load of sixteen hundred weight each, a good ordi- 

 nary cart-horse would travel England over with such a load ; drawing just as much net 

 weight as the ten horses in a heavy waggon, take each in gross weight ; and the roads 

 would never have a pressure, on one point, exceeding six hundred weight. The only 

 objection to such carriages that I see is, that each must be attended by a man. But 

 were they adopted, roads would last, I will not say ten times as long, I think they would 

 last a hundred times as long as they now do. Carriages so constructed ought therefore 

 to pass at the lowest possijjle rate of toll. The next mode is by the use of carriages 

 with six or eight wheels. About twenty years ago there were several stage-coaches con- 

 structed in this manner. Two eight- wheel coaches plied some years between Bath and 

 Bristol, and they were so constructed that each wheel supported its share of the load, 

 carrying its proportion, and no more, over every obstruction : the consequence was, 

 that when a wheel passed over a stone two inches high, the middle part of the carriage 

 rising only an eighth part of two inches, or one quarter of an inch, they were perhaps the 

 easiest coaches to passengers that ever were sat in. They had, however, one defect in 

 their construction : which was, that the two hinder axles being fixed, whenever the 

 coach varied from a straight line on the road, the hindermost pair of wheels must have 

 been dragged sideways. How the six-wheel coaches were circumstanced in this respect, 

 I had no opportunity of observing. 



3488. Double shafts have been proposed by Edgeworth, Morton, and some others, as 

 likely to divide the traction of draught cattle. B. Farey considers single shafts in 

 waggons very injurious;, the horses follow in one track, in the centre of the carriage ; 

 and the wheels also follow each other in their tracks, and cut ruts. If there were double 

 shafts, they would naturally avoid former wheel tracks, which would be less injurious 

 to the road. 



3489. J. Farey concurs in opinion with his brother, and thinks that some abatement 

 of tolls might be made to those carriages which now generally use single shafts, like the 

 farmers' carts and waggons, on tlieir adopting double shafts, so that all their horses may- 

 draw in pairs; this being applicable even to three- horse carts, as far as concerns the 

 two foremost. Stage-coaches, for the reasons here alluded to, as they all draw in 

 pairs, and very seldom follow in any previous and deep rut, do far less damage to the 

 roads than otherwise would happen ; their springs also, and swiftness of motion, contri- 

 buting, very materially, to lessening their wear of the road. 



Nn 



