996 ANNUAL REPORT OF THE Off. Doc. 



Average draft. 



Kun 1. Narrow tire in original rut, 422.0 pounds. 



Kun 2. Narrow tire in original rut, 425.0 " 



Kun 3. Narrow tire in original rut, 425.0 " 



Run 4. Narrow tire in original rut, 423.3 " 



Run 5. Broad tires over the same rut, 493.2 " 



Run 5. Broad tires over the same rut, 353.5 " 



Run 7. Broad tires over the same rut, 324.4 " 



Run 8. Broad tires over the same rut, 322.5 " 



(Old rut completely filled, and depression 



less than two inches deep made by the 



broad tires.) 



Run 9. Narrow tire in broad tire track, 393.1 " 



(Deepened rut two inches.) 

 Run 10. Broad tire in same rut. (Completely filled 



narrow tire rut), 347.3 " 



Run 11. Narrow tire in same rut. (Deepened broad 



tire rut almost two inches), 354.3 " 



Run 12. Broad tire in same rut. (Completely filled 



narrow tire rut), 342.3 " 



Run 13. Narrow tire run in same rut. (Cut rut less 



than one inch deep), 362.3 " 



Here four round trip runs were made with the narrow tires in 

 the original rut. The draft in each run is practically the same, 

 showing that it was neither diminishing nor increasing when a ton 

 load was hauled on the narrow tires, neither was the rut deepened 

 by this use. At this point the broad tire was put on this rut. The 

 first run of the broad tires shows an increased draft over the pre- 

 vious narrow tire runs of G9.G It)S., or 1G.4 per cent. In the first run, 

 therefore, the user of the broad tires could haul but 2,000 pounds on 

 a road in this condition with the same effort that the user of the 

 narrow tires could haul 2,328. However, the second run of the 

 broad tire in the same track shows a draft of only 353.5 pounds, a 

 striking reduction when compared with the first run of the broad 

 wheels, and also when compared with the average of the four runs 

 with the narrow tires. The user of the broad tires could then haul 

 with the same effort required to haul 2,000 pounds on the narrow 

 tires a load of 2,451.5 pounds on the broad tires. Thus it appears 

 that one run of the broad tiros over this road was sufficient to ma- 

 terially decrease the draft of the vehicles passing along thereafter. 



IV. Mowing Lands. 



(a) Timothy sod. Dry, firm, smooth, freshly mown. Narrow tiiv 

 cut ruts ij to 1 inch deep. No appreciable depression by broad tires. 

 Length of run 400 feet. 



Trial made July 2, 1896. 



