542 



PRACTICE OF AGRICULTURE. 



Part III. 



forms are necessary where roads branch out from or intersect each other ; and where 

 carriage roads cross the railways ; and, at turnings of the railways, great care is required to 

 make them perfectly easy. The rails of the side forming the inner part of the curve should 

 be fixed a little lower than the other ; and the rails should be set a little under the gauge, 

 so as to bring the sides nearer together than in the straight parts : these deviations in level 

 and width to be in proportion to the sharpness of the curve. The blocks and rails being 

 fixed and spiked fast, nothing more remains to be done than to fill the horse-path, or 

 space between the blocks, with good gravel, or other proper materials ; a little of which 

 must also be put on the outside of the blocks to keep them in their proper places. Tliis 

 gravel should always be kept below the surface of the rails on which the wheels are to 

 run, to keep the tracks of the wheels free from dirt and obstructions. The form of the 

 rails must be such as will free them from dirt if the gravelling is kept below tlieir 

 level. 



3470. The formation of railways, on the middle or sides of public roads, has been recom- 

 mended by Dr. Anderson, Fulton, Edgeworth, Middleton, and a few others. It does 

 not appear to us, notwithstanding all the arguments in their favor, that they would be 

 found of much use, excepting in a few cases, and then only for particular branches of 

 traffick. Formed as they are for small waggons, in order to divide the weight, they would 

 not bear with safety the weight of common farmers' two-horse carts; nor, unless the rails 

 were of a particular construction, could such carts or any other now in or likely to be 

 in general use, run on them. Suppose some alteration made on the wheels, to suit the 

 rails, then such alteration would render the wheels unsuitable for common roads. In 

 short, railroads, as constructed for ordinary purposes, could never be of much service to 

 a great thoroughfare with a mixed traffick. 



3471. A railway, with the rail ten or twelve inches broad, is the only description which 

 we conceive might be laid down along the sides of a road with advantage. It would 

 require a rib below of sufficient strength to bear waggons of any weight. This strength 

 would be communicated partly by the mass of material, but chiefly by the rib (fig. 444 a), 

 resting on a bed of bricks, or masonry below (6). Such a railroad might be used by any 

 description of carriage, light or heavy. 



444 



S472. But the best description of railroad for the sides of a highway, appears to us to 

 be one foi*med of blocks of granite twelve or fourteen inches wide, and two or three feet 

 long, imbedded on brick or masonry, or even on a layer of gravel or broken stones. Stone 

 railways of this sort appear to have been suggested by Le Large (^Machines Approvces, 

 vol. iii.) in France; and afterwards by Mathews {^Committee Examinations, May 1808,) 

 in England, but they have never been fairly tried. The best specimen we have seen is 

 in a street in Milan, where it is not so necessary, the whole breadth being very well paved. 



Sect. VI. Of the Preservation and Repair of Roads. 



3473. The preservation of a road depends in a great measure on the description of ma- 

 chines and animals which pass over it, and on keeping it dry and free from dust and mud. 

 The repair of a road should commence immediately after it is finished, and consists in 

 obliterating ruts the moment they appear, filling up any hollows, breaking any loose 

 stones, and correcting any other defect. After cleaning and this sort of repair have gone 

 on hand in hand for a longer or shorter period, according to the nature of the materials 

 and traffick of the road, a thorough repair or surface-renewal may be wanted by a coating 

 of metal of three or more inches in thickness over the whole of the road. 



3474. To preserve a road by imjyroving the wheel carriages which pass over it, all agree 

 that the wheels should be made broader than they usually are, and cylindrical : that 

 carts with two horses abreast are less injurious, than such as are drawn by two horses in 

 a line ; and that it would be an advantage to have the axletrees of different lengths. 



3475. Edgeworth, upon a careful examination, concludes, that the system of rolling 

 roads by very broad wheels should be abandoned ; and that such a breadth only should be 

 insisted upon, and such restrictions made as to loading, as will prevent the materials of 

 the road from being ground to powder, or from being cut into ruts. With this view the 

 wheels of carriages of burden should have felloes six inches broad, and no more than one 

 ton should be carried upon each wheel. 



