UTILITIES FOR HANDLING RAW MATERIAL 35 



livers coal from cars to a distributing conveyor and the latter 

 apportions the fuel among twelve or more chutes. Conveyors 

 of this same general t}^e are also used for transferring coal 

 from mine to storage pile or cars. For such utilization 

 there is selected apparatus of great simplicity of design, 

 namely, a scraper conveyor with steel flights of proper shape 

 attached to the chain and drawing the material along in a 

 steel trough. Some installations of this character have a 

 length of about 300 feet and a capacity of four tons of coal 

 per minute. 



Modifications of the belt conveyor are now to be found 

 in use in almost every branch of the industrial domain, ]:)eing 

 put to a variety of uses ranging all the way from the move- 

 ment of grain to the carriage of logs and stone. Moving 

 platforms, constructed on the endless chain plan, also have 

 an important place among the utilities for handling bulk 

 commodities. Likewise is there extensive employment of 

 traveling cableways and aerial ropew^ays wherein either the 

 impetus of gravity or hauling ropes are depended upon for 

 propulsive power. Some of the recently installed traveling 

 cablewaA^s have a span exceeding 700 feet and are adapted for 

 handling loads of from five to ten tons. The most modem 

 of all of these aerial transportation sj'stems is that desig- 

 nated telpherage, w^hereby electricity is relied upon as an 

 operative force. In this class of installations the overhead 

 trolley system of the ordinary electric railway has simply 

 been adapted to the rope railways, and by the provision of an 

 ingenious device the electric car or telpher is enabled auto- 

 matically to slacken speed when approaching a curve, resum- 

 ing the normal rate of travel when the dangerous point has 

 been passed. 



The part which cranes of various kinds have played in 

 the solution of the problem of the economical handling of raw 

 material of various kinds is indeed an important one, and there 

 has been a stead}' increase in capabilities until there are now 

 in service in the United States a number of cranes each of 

 which is capable of handling a load of one hundred tons. 



Easily the most remarkable of aU the cranes j^et con- 

 structed are the great balanced cantilevers invented Jd}- Alex- 



