434 LOGGING 
8 inches wide at the base, with outwardly sloping sides. The 
other is known as the box 6ume. 
The choice of type and size of box depends on the character 
and size of material to be transported, the amount of water 
available, and the ultimate use of the water itself. In some 
instances when water from flumes is used for irrigation pur- 
poses, the box is of larger size than is required for the sole pur- 
pose of transporting forest products. 
Lumber and log flumes rest on skids on the ground or are 
elevated on trestles. They sometiines pass through tunnels or 
cuts although these are avoided whenever possible because of 
the increased cost of construction. 
V-box. — This type of box is commonly used for lumber, 
crossties, small dimension stock, small round mine timbers, 
pulpwood,! and, when built of large size, for saw logs.^ With 
a backbone it requires less water than any other type. 
A box with a vertex angle of 90 degrees is the best because 
it has a slightly less length of side than greater or lesser angles, 
it allows the movement of logs with greater crook, it gives more 
clearance to the log than a box with a greater angle, and is more 
economical to construct because the joints at the apex can be 
fitted more easily. 
An objection sometimes raised to the use of a V-box for the 
transport of shingle bolts and other short material is that when 
the individual pieces are uneven in size and weight they do not 
all travel at the same speed, therefore, they are apt to double on 
low grades and on curves. 
1 A pulpvvood flume operated in the Adirondack Mountains of Northern New 
York was 36 inches across the top and 36 inches deep. It was supported on a 
trestle which in places was 100 feet high. The flume was 2^ miles long, had a 
capacity of sixty cords of 18-inch pulpwood per hour, and the bolts traversed 
the distance in 7| minutes, dropping into a stream down which they were 
dri\ en to a pulp mill. 
' A 5-mile log flume was constructed in Idaho ^ath an average grade of 1 1 
per cent, a maximum grade of 15 per cent, and a maximum curvature of 20 
degrees. The box was supported on trestles 16 feet apart with 4- by 8-inch 
sills, posts, and caps and 2- by 6-inch braces; 5- by 10-inch stringers with 
2- by 6-inch lateral braces and round pole supports in the center of each bent; 
4- by 6-inch bracket sills spaced from 2 to 4 feet apart depending on the 
weight carried and the strength required at loading points, and 3- by 6-inch 
braces. The box was made from 2-inch rough lumber with the cracks bat- 
tened with 1^- by 4-inch strips. See The Timberman, August, 1912, pp. 
42-44. 
