PLUMES AND FLUMING. 31 



ing the line across several miles of very soft, spongy ground with an 

 almost flat grade to contend with. This flume was also constructed 

 several years ago when the prices of labor and material were not, in 

 general, so high as at the present time. 



Probably one of the best examples of modern V-shaped log-flume 

 construction is a flume recently constructed on Rochat Creek, near 

 St. Joe, Idaho. This flume, which is unusually large and strongly 

 constructed for the purpose of handling large, heavy logs, and long 

 timbers, is said to have cost approximately $8,000 per mile for the 

 5 miles of its length. This figure includes the cost of construction 

 of a wagon road and telephone line equipment. 



DISTANCE BETWEEN BENTS. 



There is a decided difference in the opinion of different operators 

 as to the 'distance that the bents should be placed apart in flume 

 construction, some contending for a 16-foot bent or length of stringers 

 and box on all tangents, while others favor a 12-foot bent. Each has 

 its merits. If a cheap flume for temporary use and medium capacity 

 is desired, then one with 16-foot bents and boxes will usually answer 

 the purpose; that is to say, if the life of the flume is only desired to be 

 from 4 to 6 years. If large material is to be handled and the life of 

 the flume is to be for a long period of time, then the construction 

 work should be stronger and more lasting. If heavy material is to 

 be handled, even the 30-inch V box flume might well be constructed 

 with bents 12 feet apart, and in some cases even less if durability and 

 strength are essential features. 



The trouble with the bents 16 feet apart usually is that the stringers 

 are more apt to sag or twist, thereby letting the box sag on one side 

 or the other. This usually causes the water in the flume to slop 

 over at the point of sagging, and the water softens and washes out the 

 foundations under the bents, so that eventually the section of the 

 flume where this occurs becomes uneven in grade and therefore 

 leaky. The result is that the work of repair is much increased and 

 breakdowns in the transportation operations are more frequent. It 

 is usually advisable to place the brackets or arms not more than 4 

 feet apart on any size or style of flume. When placed farther apart 

 than this it usually permits of too much spring to the box boards, 

 and springing means leaks, which wash out the foundation of the 

 bents and in many kinds of soil, especially on side hills, causes 

 expensive slides or washouts. 



The same general principle applies in connection with the lining of 

 a box, and there is much difference of opinion on the value of the 

 different types of construction. It is contended by some operators 

 that the 1^-inch box lining, strengthened with 1 by 4 inch battens 



