Nc. 6. DEPARTMENT OF AGRICULTURE. 1001 



the cornfields, wheat stubble, etc., of the farm on the narrow tires, 

 11 load of 2,U7U pounds, could have been hauled on the broad tires 

 without doing any perceptible damage to the fields. 



VII. Plowed Ground. 



(a) Not harrowed. Many large clods; surface rough. Large clods 

 crushed by wdde tires. Narrow tires pushed them aside. Trial made 

 September 12, 1896. 



Average draft. 



Narrow tires, 509 . 9 pounds. 



Broad tires, 382.6 



Difference in favor of broad tires, 127 " 



Percentage difference, 33 .2 



(b) Same as "(a)" except ground prepared for seeding. Surface, 

 smooth; fairly compact; fine tilth. 



Average draft. 



Narrow tires, 466.5 pounds. 



Broad tires, 323 " 



Difference in favor of broad tires, 143.3 " 



Percentage difference, 44.3 



Two trials w^ere made on plowed fields, one over freshly plowed 

 ground before the clods had been reduced by tillage; the second on 

 the same ground after it had been reduced to a fine tilth as for seed- 

 ing. In the first trial on the freshly plowed ground, the difference 

 in favor of the broad tire was 127.3 pounds, or 33.2 per cent, practi- 

 cally one-third less than the narrow tire. In the second trial the 

 difference w^as 143.3 pounds, or 44.3 per cent, in favor of the broad 

 tire. 



Proper Width of Tire. 



It is believed that the six inch tire will prove more satisfactory, 

 all things considered, for a combination farm and road wagon than 

 will any other width. The three or four inch tire is unsatisfactory 

 in running over the ruts made by the narrow tires, inasmuch as 

 these ruts are wide enough at the top to allow the four inch tire 

 to sink down at least a portion of their depth, thereby greatly 

 increasing the side friction and the draft. The six inch tire on the 

 other hand will run over these ruts and in a few trips completely fill 

 them. Again, the three or four inch tire on a road partially dry on 

 top and spongy underneath will not show the same saving of draft 

 as the six inch tire, inasmuch as deeper ruts will be cut by them. 

 From every point of view the six inch tires will be very much more 

 satisfactory for farm use. On the road, in but two conditions of the 

 surface, would the four inch tires show a lighter draft than the six 



