202 SCIENCE OF SUCCESSFUL THRESHING. 



and come off, and it is best to stop in time and keep them 

 in good condition to start again. 



Leather Belts. All leather belts should be run hair side 

 to the pulley. Some years ago mechanics and engineers 

 disagreed as to which side of the leather should be next to 

 the pulley, but it has been shown that belts last longer and 

 transmit more power when run hair side to the pulley. The 

 reason is that the flesh side is more flexible and will more 

 readily accommodate itself to the curve of the pulley. If 

 the more rigid hair side be obliged to stretch every time it 

 goes around a pulley, it will crack, in time. When leather 

 belts become hard, they should be softened with neatsfoot oil, 

 for a flexible belt will transmit more power than a hard, stiff 

 one. The mineral oils used for lubricating purposes rot 

 leather rapidly and consequently, belts should be kept as 

 free from them as possible. 



A Rubber Belt should always be put on with the seam, 

 which is near the center, and covered with a narrow strip of 

 rubber, on the outside, and not next to the pulley. The 

 cleaner a rubber belt is kept, the better. No dressing of 

 any kind should be used. Anything of a sticky nature adher- 

 ing to it, will have a tendency to pull off the outer coating 

 of rubber and greatly injure the belt. Oils of all kinds 

 should be carefully avoided, and should a rubber belt acci- 

 dentally become covered with oil, it is best to wash it off 

 with soap and water. The best place to store rubber belts is 

 in the cellar, as dampness and darkness tend to preserve them 



