LOGGING IN NORTH-WEST AMERICA. 153 



route can be obtained, and the best grades, curves, and probable 

 cost determined before the work is taken in hand. Water-supply 

 and grade serve to determine the possibility of fluming. The 

 grades permissible to fluming vary from i % as a minimum to 

 25 % or more ; 2-6 % grades are the most economical and 

 efficient. 



Flumes with grades steeper than 25 % become more or less 

 a wet chute, and of course a chute is just a trough built 

 of round timber on which logs are transported up or down a 

 grade (generally down), either by animal power or by gravity. 

 On the journey from Lethbridge to Spokane Wash, many chutes 

 may be seen on the steep mountain sides where all the timber 

 has been removed. 



The available water-supply will invariably determine the type 

 of flume — whether square or V-shaped. The latter type is 

 considered the best and most economical for all classes of 

 timber, and is usually the type employed by loggers in the 

 western forests. It excels because it can be operated with less 

 water than other types, the water is confined and, for the 

 amount used, it has the greatest carrying power, and owing to 

 the shape and confined space, saw-logs, and especially short 

 pieces like sleepers, pit-props and fence-posts are kept running 

 straight and are therefore less likely to cause a jam. The 

 water confined below the bottom of the stick and the sides of 

 V tends to lift the log, this keeps it up and also prevents it 

 from rubbing too much against the sides of the flume. 



In the construction of the V-shaped flumes experience proves 

 that the 90° angle is the best for all purposes. The usual 

 procedure is to erect a small sawmill near the upper end of 

 the flume location and saw out the material required for con- 

 struction. As the work proceeds the lumber is floated down as 

 it is required. Saw-logs, poles, sleepers, pit-props, fence-posts, 

 etc., can all be floated down cheaply and quickly to the main 

 saw-mill dam and sorted out. 



The C. P. R. flume most of their timber at Yahk, southern 

 British Columbia. In the autumn when the water becomes- 

 scarce, and when the splash dams are empty, they make use 

 of an iron apron which is made to fit the flume. This apron 

 dams back the water in sufficient quantity to give force enough 

 when released to set the logs agoing (Plate VII. Fig. 2). With 

 judicious loading this helps to prevent the timber jamming. 



VOL. XXXVI. PART H. L 



