544 PRACTICE OF AGRICULTURE. Part III. 



would be paramount to every thing that could be urged in favor of the narrow 

 wheels. 



3481. M' Jdam thinka a waggon wheel of six inches in breadth, if standing fairly on 

 the road with any weight whatever, would do very little material injury to a road well 

 made, and perfectly smooth. The injury done to roads is by these immense weights 

 striking against materials, and in the present mode of shaping the wheels they drive the 

 materials before them, instead of passing over them. If a carriage passes fairly over 

 a smooth surface, he says, that cannot hurt the road, but must rather be an advantage 

 to it, upon the principle of the roller. On being asked, " Are you not of opinion that 

 the immense weights carried by the broad-wheeled waggons, even by their perpendicular 

 pressure, do injury by crushing the materials ?" he answered, " On a new-made road the 

 crush would do mischief, but on a consolidated old road, the mere perpendicular pressure 

 does not do any. But there is a great deal of injury done by the conical form of the 

 broad wheels, which operate like sledging instead of turning fairly. Tliere is a sixteen- 

 inch wheel waggon, which comes out of Bristol, that does more injury to our roads, than 

 all the travelling of the day besides." 



3482. With regard to regulating the weight to be carried on wheels, Farey judiciously 

 observes, that though it is not easy to state any one scale that would be generally appli- 

 cable for each breadth of wheels below six inches, there should be a rate fixed, which 

 would apply to ordinary or gate-tolls ; and at the weighing machines additional or what 

 may be called machine tolls, should be levied upon all carriages which exceeded the 

 weight, to be regulated in an increasing scale for each breadth of wheel, so as very greatly 

 to discourage, but not ruinously to prohibit the occasional carrying of large weights upon 

 any wheels. 



3483. Axletrees of different lengths have been proposed by some engineers with a view 

 of preserving the roads. On this subject Paterson observes, " At present the axles of 

 all kinds of carriages are made to one length, so that their wheels all run at the same 

 width, and in the same track, than which nothing could be more fitly devised for the 

 destruction of the roads. I would, therefore, propose, that the length of the axletrees 

 should be so varied, that the wheels of the lighter description of carriages should run 

 two inches narrower than the present track ; and that the axles for the more weighty 

 carriages should be increased in length, so that their wheels should run from one to four 

 inches beyond the present track. I would also propose, that mails, and other heavy 

 coaches, should be so constructed, tliat the hind wheels should follow, either two inches 

 within, or two inches outside the track of the fore-wheels, as might be considered most 

 proper. Were the axletrees of all kmds of carriages to be of various lengths, as here 

 proposed, we should have no rutted roads. The stones now displaced by the wheels of 

 one carriage, would be replaced again by the next carriage that came up, having its axle 

 of a diflTerent length ; and in the same manner would the hind wheels repair the injury 

 done by the fore wheels of a carriage. If this plan was to be acted upon all over the 

 kingdom, it is evident that it would have a very beneficial eiFect on the roads ; and if it 

 should be found thus to contribute to the keeping the roads smooth and even, it is also 

 evident that it must contribute, in the same proportion, to the comfort of travellers of 

 every description, and also to the ease of the beast of draught." 



3484. J. Farey is of opinion that varying the length of axles, so as to prevent their 

 running in the same track, would be very beneficial. This he particularly stated to the 

 Board of Agriculture, with an example of the tolls over a new road in Derbyshire, 

 which are regulated according to the length of the axle. 



3485. The division of weight has been proposed l)y Fry as a means of preserving roads : 

 that is to say, the division of the power, which any carriage may possess, to crush or 

 destroy the materials of the roads ; and the division of the power which any carriage 

 may possess, to resist the power of the horses drawing such carriage. A man can break 

 an ordinary stick, an inch in diameter, across his knee, but if he tie ten of these sticks 

 together, he could not break them if he tried ten times, nor if he tried a thousand times ; 

 although, by these thousand efforts, he might have broken a thousand such sticks sepa- 

 rately. A stone might be of such a size and texture that a strong man with a large 

 hammer might break it into pieces at one blow; while a boy vv'ith a small hammer, 

 striking it with one-tenth part of the force, might strike it a thousand times, applying in 

 the whole one hundred times the power upon it that the man would have done, without 

 producing the same effect. So it is with the pressure of wheels on the materials of the 

 roads. Suppose a stone, the size of a man's fist, to be detached on a firm part of the 

 road, and a waggon-wheel, pressing with the weight of two tons, were to pass over it, 

 the consequence would be that it would crush it to powder. But suppose these two 

 tons to be distributed into forty wheel-barrows, of one hundred weight each, and they 

 were to pass over it in succession, the only effect likely to be produced would be a 

 trifling rounding of its corners : nor would probably five hundred such wheel-barrows, 

 of twenty-five tons, crush the stone so completely as the single waggon-wheel. Nor do I 



