112 



JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



the draught required for 2,000 lbs. on the narrow tires. When 

 the surface was covered with two or three inches of very dry 

 loose dust the results were unfavourable to the broad tire. On 

 clay road, muddy and sticky on the surface and firm under- 

 neath, the results were uniformly unfavourable to the broad 

 tires. On the other hand, on clay road deep with mud and dry- 

 ing on top, or dry on top and spongy beneath, numerous tests 

 were uniformly favourable to the broad tire. The difference 

 ranged from 52 to 61 per cent. ; on the average about 3,200 lbs. 

 could be hauled on the broad tires with the draught required for 

 2,000 lbs. on the narrow tires. It was in this condition of dirt 

 road that the broad tires showed to greatest advantage. As the 

 road dries and becomes firmer the difference between the broad 

 and narrow tires gradually diminishes, until it falls to about 25 

 to 30 per cent, on dry, hard, smooth dirt, gravel, or macadam 

 road, in favour of the broad tire. On the contiary, as the mud 

 becomes softer and deeper, a condition is at length reached when 

 the mud adheres to both types of wheel ; here the advantage of 

 the broad tires ceases entirely and the narrow tires pull mate- 

 rially lighter. Generally it may be said that during the greater 

 part of the year, and at times when the dirt roads are most in 

 requisition and w T hen their use is most imperative, the broad- 

 tired wheels have a considerably lighter draught than the 

 narrow-tired. 



Many tests on meadows, pastures, stubble land, corn ground, 

 and ploughed ground in every condition, from dry, hard, and 

 firm to very wet and soft, showed without any exception a large 

 difference in draught in favour of the broad tires — a difference 

 ranging from 17 to 120 per cent. The investigations further 

 showed that six inches is the best width of tire for a combina- 

 tion farm and road wagon, and that both axles should be the 

 same length, thereby securing that the front and hind wheels 

 shall run in the same track. This inquiry differs in character 

 from some of the abstruse problems the solution of which is 

 attempted at American experimental stations ; but there can be 

 no question as to its utility. 



