ON THE RESISTANCE OF ROAD VEHICLES TO THACTIOX. 341 



Table III.— Effect of the Width of Ti/ res on Traction. 



Description of tlio 

 Roacl Surface 



Sod . . . . 

 Roads. — Earth hard . 



,, ,. muddy 



Sand.— Hard . 



„ Deep 

 Gravel 

 Wood block : round . 



Resistance to traction in lb. per ton of 2,000 lb. 



44" and 4G" Wheels 



Tyres 



199 

 871 



51 



4" 



304 

 164 



117 

 70 



44" and 54" 



Tyres 



n" 



236 

 141 



83 

 35 



4" 



2.14 

 168 



80 

 46 



44" and 54" 



Table IV.— Effect of Speed on Tractive Force {after Mori n). 



