FLUMES AND FLUMING. 7 



the lining of boxes is constructed with two thicknesses of boards 

 with the joints broken by varying the width of the boards, as shown 

 in figure 2. Another form of box construction is by the use of a 

 single thickness of boards with "battens" to cover the joints, the 

 battens being spiked over the joints on the outside in the sections 

 between the brackets or arms, as shown in figure 3. There is still 

 another form of box construction in which the battens are continuous. 

 (See fig. 4.) In such cases the battens are "cut in" or set into the 

 arms or brackets on the outside of the V, thus making a continuous 

 "broken joint." 



There are certain individual advantages in each of these different 

 styles of box construction, and the right one to use is a question 

 which the prospective operator must always determine for himself. 

 The use of the continuous battening running under the arms requires 

 some cutting into the bracket frames or arms in order to let the 

 battens pass through them, and consequently, to a certain extent, 

 weakens the arms. This usually necessitates a heavier arm than 

 would be required if the battens only reached from one arm to 

 another and were spiked over the joint entirely independent of the 

 "arm." On the other hand, the continuous battens are held firmly 

 in place by the arms and braces, and it is almost impossible for bat- 

 tens properly put on in this manner to get out of place while the 

 arms and braces are firmly in position. 



The use of the double-lined box with joints broken is contended 

 for by some operators on the ground that it is always necessary to 

 replace the fining of the boxes occasionally on curves and in places 

 where the passage of lumber wears most rapidly. It is also con- 

 tended that the doubled box retains moisture much better between 

 the two linings and, therefore, will permit of the flume standing idle 

 without any water rumiing in it, for repairs or other reasons, for a 

 much longer period of time without the boxes becoming thoroughly 

 dried out and "checking" so that the flume will leak, or warping out 

 of shape and position, or drawing the nails used to hold the lining in 

 place. The battening between the different arms or frames makes 

 it possible to use almost any width or thickness of material for this 

 purpose. It can be put on or taken off without interfering with any 

 of the other forms of construction, and this feature also has its 

 ardent supporters. 



TRIANGULAR BLOCKS IN THE BOTTOM OF THE ""V." 



In some instances it has been thought advisable to fill the bottom 

 of the V in a flume with a triangular section of wood sawed in such 

 form that it would fit snugly into the bottom of the V on the inside. 

 Some constructors claim that this block serves the twofold purpose of 

 reducing the amount of water necessary in operating a flume and 



