Page:Popular Science Monthly Volume 62.djvu/79

Rh 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 nights 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, being put to a variety

of uses ranging all the way from the movement 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 ropeways wherein either the impetus of gravity or hauling ropes are depended upon for propulsive power. Some of the recently installed traveling cableways have a span exceeding 700 feet and are adapted for handling loads of from five to ten tons. The most modern of all of these aerial transportation systems is that designated 'telpherage,' whereby 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 automatically to slacken speed when approaching a