6. That rawhide has much greater adhesion than tanned leather, giving a coefficient of 100 per cent. at the moderate slip of 5 ft. per minute.
7. That a velocity of sliding equal to .01 of the belt speed is not excessive.
8. That the coefficients in general use are rather below the average results obtained.
9. That when suddenly forced to slip, the coefficient of friction becomes momentarily very high, but that it gradually decreases as the slip continues.
10. That the sum of the tensions is not constant, but increases with the load to the maximum extent of about 33 per cent. with vertical belts.
11. That, with horizontal belts, the sum of the tensions may increase indefinitely as far as the breaking strength of the belt.
12. That the economy of belt transmission depends principally upon journal friction and slip.
13. That it is important on this account to make the belt speed as high as possible within the limits of 5,000 or 6,000 ft. per minute.
14. That quarter-twist belts should be avoided.
15. That it is preferable in all cases, from considerations of economy in wear on belt and power consumed, to use an intermediate guide pulley, so placed that the belt may be run in either direction.