WATER TRANSPORTATION 



27 



Obviously, the skidding capacity of an engine is not proportioned exactly to its loading capacity. The 

 amount of logs skidded per day varies according to the density of stumpage and to the obstacles met. 

 The price of a combination skidder and loader is •■^•2,000 for a 7 X 10 engine and -v 2,500 for a 8'/, X 12 

 engine. The price of self-propelling machines is over twice these figures. 



Self-propelling combined ground -skidder and loader. Lidgerwood Mfg. Co., Liberty St., New York. 



The regularity of the mill run and the regularity of the movement of the trains are best subserved 

 by independent skidders and loaders. 



In the pineries of the South it is stated that the entire e.xpense of cutting, skidding, and railroading 

 does not exceed an average of #2 per 1,000 feet b. m. Skidding by horses, with 2-wheel trucks, is said 

 to be about |^1, and skidding by 4-mule waggons is said to be about i^l more expensive than steam skidding, 

 under otherwise equal conditions. 



It is obvious that steam skidding is compatible only with a system of clear cutting. It does not 

 answer the purpose of selective cutting, for silvicultural reasons as well as for economic reasons. 



PARAGRAPH VIII. 

 WATER TRANSPORTATION. 



Logs or lumber are driven loosely, floated in rafts, or flumed. 



(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 TOO. Heavy species might be deadened 

 some months before driving, like teak in India or cypress in the South, to attain this end, provided that 

 attacks from fungi or insects, on the deadened trees, can be avoided. 



Under favorable conditions, where the creeks are narrow and well watered, no special arrangements 

 for driving are required. 



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. 



