FOREST UTILIZATION 23 



endless cable ("tripline") running into the dis- 

 trict to be logged over a number of tackle blocks. Zig- 

 zags can be made by using tackle blocks on the hauling 

 line as well. One engineer and one fireman are all the 

 crew required in addition to two loaders. Frequently 

 the engine loads logs on railroad cars at the same time. 

 The engine's cylinders are about 8 inches by 10 inches. 

 Engines are moved from place to place by their own 

 power. Price for an engine f. o. b. Biltmore is $1,400. 

 Boilers are of the upright type. The wire cable is 

 usually made of 6 strands, each containing 19 wires, 

 wound around a hemp center. Running cables should 

 never be galvanized. The proper load of a cable is only 

 one-fifth of the breaking strain in tons. Steel ropes 

 (cables)' have twice the strength of charcoal iron ropes. 

 One-inch steel wire cable costs igc a foot, weighs about 

 1 1 /2 pounds per foot and has a breaking strain of 33 

 tons. Its proper load is 6 tons only. Silviculturally this 

 method of steam logging is objectionable. 



IX. WATER TRANSPORTATION. 



Logs or lumber are driven loosely or floated in rafts. 



A. Loose driving is a method used in eastern America for short 



logs, pulp wood and firewood. 



Specific gravity of material driven must be reduced below i.oo. 

 Heavy species might be deadened a year before driving, like 

 teak in India, to attain this end, provided that attacks from 

 fungi or insects, on the deadened trees, are not to be feared. 

 Under favorable conditions, where the creeks are narrow and 

 well watered, no special arrangements for driving are re- 

 quired. 



I. Splash dams. The proper site for a splash dam is the 

 rocky narrows of a water course below a broad bottom 

 of little fall, or else at the outlet of a natural lake. 

 Large splash dams must be placed on rock foundations. 

 The expense of building increases at a cubic ratio with 

 the height of the dam. 



Splash dams built in tributaries are preferable to dams 

 in the main creek, provided that they can be filled 

 quickly enough. 4 

 A system of dams of first, Second and third importance 



is frequently formed. 



The distance of effectiveness of a dam depends on the 

 size of the water reservoir, the width of the water 

 course below the dam, and the rapidity of its fall. On 

 "Big Creek" in Pisgah Forest the distance, of effective- 

 ness was four miles. 



Splash dams meant to be permanent must be built of 

 stone and are exceedingly expensive. 



