ON DRAUGHT. 



441 



wheels, and nine-inch wheels seven inches outside, they are then called 

 straddlers, and are allowed to carry a fi;reater weight than if not so. The 

 original intent of these was most excellent; but the effect has been defeated 

 by the carrier or other person not only making the bed or axle contrary to 

 what was intended, but also by carrying with them a false collar, with a 

 joint therein, to put on and take off at pleasure; so that they have no 

 great difficulty in making the wheels straddlers a little before they come 

 to a weighing machine, and making them not so when they have passed 

 the same.' 



On modern roads such an arrangement would hardly be beneficial even 

 to the road itself, and would nearly double the amount of draught. 



Too great care and precaution cannot be taken to insure the wheels 

 running in the same track. Let it be remembered that, on a good road, 

 the forming the rut is the cause of three-fourths, and oftener five-sixths of 

 the whole resistance. Narrow wheels, therefore, running in the same 

 track, without doubt offer the least resistance, provided there is surface 

 sufficient to bear the weight, without destruction to the foundation of the 

 road. 



Six inches in breadth of the flat or cylindrical part, a b, fig. 36, inde- 

 pendent of the rounded edges, will be quite sufficient, in a wheel of ordi- 

 nary size, to bear a ton without injury to the roads, if in good condition; 

 and according as the weight upon each wheel is more or less than this, the 

 breadth should be proportionably increased or diminished. 



While upon the subject of wheels, it may be as well to state the several 

 new modes of constructing wheels lately introduced, which severally possess 

 their merits and disadvantages. The last improvement is that known 

 under the name of ' Jones' patent wheels. 



It consists in making the felloe of a single ring of cast iron. The nave, 

 which is also of cast iron, is suspended in the centre by eight wrought iron 

 rods: these rods are crossed or alternately dished inwards and outwards, 

 to give stiffness, which is thus obtained without affecting the cylindrical 

 form of the whole. 



Fig. 37 and 38, represent different views of this wheel, FF being the 

 cast iron felloe, S S the spokes, and N the nave. 



These wheels have been adopted to a great extent in London, and 

 therefore we may conclude that they are found to answer ; but they are 



F,cf. 37. 



Fig. 38. 



