WHEEL CARRIAGES. 105 



levers, in proportion to their various sizes. All 

 wheels, but especially small ones, are apt to sink 

 into the ground over which they pass, and thus 

 produce a constant obstacle to their progress, which 

 the large ones most easily overcome. 



In all four-wheeled carriages, the fore-wheels 

 are made of a less size than the hind ones, in order 

 to enable them to turn in less room ; but the car- 

 riage would go much easier, if the fore-wheels were 

 as high as the hind ones. 



It is plain, that the small wheels must turn as 

 much often er round than the great ones, as their 

 circumferences are less. And, therefore, when 

 the carriage is loaded equally heavy on both axles, 

 the fore-axle must sustain as much more friction, 

 and consequently wear out as much sooner than 

 the hind axle, as the fore-wheels are less than the 

 hind ones. And though this points out that the 

 greatest weight should be laid upon the large 

 wheels, yet it is generally the practice to put the 

 greatest load over the small wheels, which not 

 only makes the friction greatest where it should 

 be least, but also presses the fore-wheels deeper 

 into the ground than the hind wheels, notwith- 

 standing the former are with more difficulty drawn 

 out of it than the latter. 



It is true, that when the road is much up-hill, 

 there is danger in loading too much the hind 

 wheels, least the fore-wheels should be tilted up. 



It is well known that a great outcry was raised 

 by the generality of the carriers, against the broad 

 wheel act ; and that it was difficult to persuade 

 them to comply with it, even though they were al- 

 lowed to draw with more horses, and carry greater 

 loads than usual. Their principal objection was, 

 that, as a broad wheel must touch the ground in a 



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