Ne. 6. DEPARTMENT OP AGRICULTURE. 99a 



(m) Clay road. Mud deep, still", and begiiming to dry on the sur- 

 face. At one end of the run was soft mud on which water was stand- 

 ing. The narrow tire made a rut 7 inches deep. Length of run 400 

 feet. March 19, 1897. 



Average draft. 



Narrow tires, 825.3 pounds. 



Broad tires, 551.9 " 



Difference in favor of broad tires, 273.4 " 



Percentage difference in favor of broad 



tires, 49.3 " 



(n) Clay road. Muddy, slightly frozen on top, but not enough to 

 bear the load on either set of wheels. Narrow tires made ruts 12 

 inches deep in places. Length of run 400 feet. 



Average draft. 



Narrow tires, 549 . pounds. 



Broad tires, 447.6 " 



Difference in favor of broad tires, 101.4 " 



Percentage difference, 22 



(o) Clay road, very soft and sticky. Old ruts 18 inches deep, full 

 of water. Narrow tire run first. Broad tire rut about 6 to 8 inches 

 deep, and gathered the mud, filling the wheel. Trial made April 9, 

 1896. Length of run 400 feet. 



Average draft. 



Narrow tires, 321 .7 pounds. 



Broad tires, 514 . 1 " 



Difference in favor of narrow tire, 192 . 4 " 



Percentage difference, 59 - 



In this trial the mud was stiff enough to adhere to the rim and 

 spokes of the wheels, and the difference in the amount of mud gath- 

 ered and transported by the broad and narrow tires is so great that 

 the draft of the broad tires was 59 per cent, higher than that of 

 the narrow tires. After carefully watching the dirt roads in this 

 locality for two years, this is the only time they were found in that 

 condition. 



In the two years covered by these trials, only two conditions of 

 the dirt roads have been found in which the narrow tire pulled 

 lighter than the broad tire, viz: when soft, either muddy or very 

 dusty, on the surface and hard underneath; and when the mud was 

 deep and sticky so that both sets of wheels cut deep ruts and the 

 mud adhered to the wheels. In the nature of the case, both of these 

 conditions of the road are of short duration. In all other conditions 

 of dirt roads, the broad tire has shown a materially lighter draft than 

 the narrow tire. 



Clay road. Hard and dry. Ruts previously made by narrow tire 

 2.5 inches deep, with rough ridges of earth on either side. Walls of 

 63—6—1901 



