Report on the Trials of Implements at Bedford. 083 



the former is only a small proportion of the total draught — about 

 one-twentieth, — while the remaining nineteen-twentieths repre- 

 sent resistance on the road. 



No experiments were made to test friction at the axle, and as 

 this is only a trifling proportion, the actual results in the trials 

 show nearly how far the resistance on the road was influenced by 

 the diameter of the wheels, the form of the wheels, the width of 

 tyres, form of tyres, and steadiness of load by the use of springs 

 and from other causes. 



In order to see the effect of diameter of wheels, Hayes and 

 Son's cart. No. 1445, in Class XXVII., may be compared with 

 their waggon. No. 1431, in Class XX. 



As the hind wheels of the waggon are 5 feet in diameter, and 

 therefore the same as the cart wheels, it may be assumed that the 

 proportional force required to move the weight resting on the hind 

 wheels of the waggon, will be nearly the same as that required to 

 move the total weight resting upon the wheels of the cart. The 

 width of tyre in the waggon is less by 1^ inch than in the case 

 of the cart ; and in order that this may be less taken into account, 

 we shall only consider the mean draught on the macadamised 

 road, where, as will be seen afterwards, the width of tyre had 

 much less effect in altering the draughts than on the field course. It 

 will also be noticed that the inclination of the wheels is greater in 

 the waggon than in the cart, which will have some effect, although 

 not very much, in increasing the draught of the waggon. 



By a short calculation we shall find that, in order to pull the 

 cart, a force of one pound is exerted for every 58*76 lbs. resting 

 upon the wheels, and by dividing the total weight resting upon 

 the hind wheels of the waggon by 58*76 we find that 71*7 lbs. 

 of the mean draught is absorbed in moving the latter weight ; 

 we have thei'efore remaining 105 * 9 lbs, which is the mean 

 draught expended in moving the weight on the fore wheels of 

 the waggon. Thus we see that 1 lb. of draught is expended in 

 moving every 35 * 1 lbs. of weight resting on the fore wheels of 



