FOREST UTILIZATION 37 



at the rim, the carriage hanging between the wheels a few 

 inches above the rail. Cars are balanced by a telescopic 

 rod and kept in balance, like a bicycle, by the motive power 

 itself, which consists of an animal hitched, in a frame along- 

 side of the carriage. 

 The mono rail system might be applicable in the transporta- 



tation of bark, cordwood and minerals. 

 H. Cable way logging. 



The logs are suspended from a cable and are not dragged 

 on the ground. 



I. On steep slopes, the grade being 35% to 50%, the logs 

 slide down by gravity, being suspended from two 

 trolley blocks held apart by a strong rod or pole, about 

 15 feet long. At the upper ead of the cable, curved iron 

 rails lead, like a bridge switch, onto the cable. The 

 cable is kept tight by heavy drums, over which the 

 cable runs at the ends. It is said to wear out in about 

 eight years. 



The upeed of the block carriage is regulated by manila 

 rope, wire or light \vire cable, and the empty block 

 carriage is carried backward by the same rope without 

 any motive power other than that of a loaded block 

 carriage going down hill. Proper switches allow the 

 empty block carriage to pass the loaded one at a 

 half-way point. The price of i-inch wire cable is 

 about 190 per foot. 



In Switzerland lines two miles long are found, without 

 any supports. In the Hartz Mountains supports are 

 given every 700 feet and the expense is $800 per mile 

 for entire equipment. 



In Oregon and western North Carolina short cable con- 

 duits of this character are in successful use, and in 

 India (in the Himalayas) the most extensive plants of 

 this character are said to exist. 



II. In swamps of the Atlantic coast, where railroading is 



difficult, the system of the Trenton Iron Co. and of the 



Lidgerwood Manufacturing Co. have been tried which 



move the block carriage holding the logs in suspense 



over a cable either by steam power or by electricity. 



(a) In case of steam power, the engine is 



placed either on a scow swimming in 



the swamp, in the river, in the logging 



canal cut by powerful dredges, or on a 



railroad car, the logging outfit costing 



about $7,500 per mile (including lateral 



rig), consisting- of: 



One-inch carrying cable and double traction 

 rope; 



