BELT POWER TRANSMISSION. LXXXIX. 
Dry single leather belt, 6” wide, cemented only, flesh side to 
pulley. Endless. 
Lbs. tension as before. Horse power. Nearest coeff. 
ee IS 4°6 
400 6-9 3 
496 8-2 . 
650 111 ‘i 
Balata, 5-ply, 6” wide, new. Wire lacing. 
Lbs. tension as before. Horse power. Nearest coeff. ° 
275 3°8 
400 54 a 
490 6°5 7 
650 8:7 9 
The coefficients are deduced to the nearest first place of 
decimals. 
The belts were new in each case. The pulleys were smooth 
with the ordinary turned surface and were kept clean from any 
adhesive substance due to any previous test. 
In the above experiments the results would appear to séuitirtn 
the practical superiority of leather, and this more especially 
applies as leather is not in its best condition when new, whereas 
the woven and rubber belts with the adhesive substances applied 
to them externally in manufacture are at their best, and will lose 
efficiency as the substance wears off. 
From the data derived from the experiments, and following a 
graphic system which the author first noticed in the American - 
Machinist, the diagrams have been prepared, shewing size of 
pulley, speed per minute, width of belt, and horse power trans- 
mitted ; assuming a total tension on the tight side of the belt of 
60Ibs. per inch of width, this being as great as can be recommended 
for durable effect. 
As far as the author is aware, the only examination of the com- 
parative efliciency of belts and ropes was made by the Society of 
Industry of Northern France in 1895, when careful comparison 
