BELT POWER TRANSMISSION. XCl. 
Link belts are commonly secured by steel pins, and in more 
recent construction are flexible longitudinally to afford better 
grip in crowned pulleys. For high speed machinery with constant 
load driven by variable speed motor such as a gas engine, or con- 
stant power driving a variable load, the leather pin link belt will 
give most satisfactory results. This class of belt would appear 
on cursory examination to be incapable of long wear and 
durability, but as a matter of fact, its durability and elasticity 
is remarkable. It is customary to drive link belts at much higher 
tensions per unit of sectional area than is permitted by solid 
leather bands. Link belts are found to stretch to 157% in excess 
of their original length without damage, and may be safely used 
at very high speeds on pulleys as small as 9” diameter, and being 
weighty for its capacity, it usually runs free from shaking-waves., 
Where the distances between centres are short, and the arc of 
contact consequently small, the link belt is commonly applied. 
The author is, however, of opinion that in all such cases a system 
of leading pulleys permitting the use of a longer belt—the main 
distance between centres remaining the same—is much preferable. 
Both pulleys being then embraced to 180° and greater elasticity 
of belt obtained. 
The author has observed cases where the tension in belt and 
stress in journals could have been reduced more than 50% by this 
simple expedient, with the same transmission of load. 
In situations where the excessive heat or dryness, leather is 
found to become dry and hard, the use of raw-hide belting is 
advisable. It has a high efficiency and wears well, being snbject 
however to a greater stretching than leather. During use it has 
a tendency to exude the stuffing used in its manufacture and clog 
the pulley face, and while the transmitting efficiency is increased 
the pulley becomes uneven and the durability of the belt affected. 
The pulleys should be kept clear of such adhesions. Among the 
simple belts, a class known as “ Patent Edge” has much favour 
among electrical engineers; it consists of a single belt witha 
double edge, and has practically the flexibility of a single with 
