OF WHEEL-CARRIAGES. 99 



very little way, the small wheels ought in all reason to LECT. 

 be loaded with less weight than the great ones : and then ^-v-^ 

 the heavier part of the load would be less jolted upward 

 and downward, and the horses tired so much the less, as 

 their draught raised the load to less heights. 



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

 there may be danger in loading the hind part much hea- 

 vier than the fore part; for then the weight would over- 

 hang the hind-axle, especially if the load be high, and 

 endanger tilting up the fore-wheels from the ground 

 In this case, the safest way would be to load it equally 

 heavy on both axles ; and then, as much more of the 

 weight would be thrown upon the hind-axle than upon 

 the fore one, as the ground rises from a level below the 

 carriage. But as this seldom happens, and when it does, 

 a small temporary weight laid upon the pole between the 

 horses would overbalance the danger ; and this weight 

 might be thrown into the wagon when it comes to level 

 ground ; it is strange that an advantage so plain and 

 obvious as would arise from loading the hind-wheels 

 heaviest, should not be laid hold of, by complying with 

 this methed. 



To confirm these reasonings by experiment : let a 

 small model of a wagon be made, with its fore-wheels 

 2i inches in diameter, and its hind-wheels 4i ; the whole 

 model weighing about 20 ounces. Let this little car- 

 riage be loaded any how with weights, and have a small 

 cord tied to each of its ends, equally high from the 

 ground it rests upon ; and let it be drawn along a ho- 

 rizontal board, first by a weight in a scale hung to the 

 cord at the fore-part ; the cord going over a pulley at . 

 the end of the board to facilitate the draught, and the 

 weight just sufficient to draw it along. Then, turn the 

 carriage, and hang the scale and weight to the hind 

 cord, and it will be found to move along with the same 

 velocity as at first: which shews, that the power re- 

 'inired to draw the carriage is all the same, whether the 

 H 2 



