32 



BULLETIN 87, U. S. DEPARTMENT OF AGRICULTURE. 



firmly nailed over the joints on the outside, is much more satisfac- 

 tory than the doubled 1-inch boards. It is contended that the 1-inch 

 doubled box is not as rigid as the 1^-inch lining reinforced by the 

 battens, and that the doubled box permits of a constant spring when 

 heavy timber is passing through the flume. This causes the boards 

 gradually to work apart and fill in between the two courses with 

 bark and sediment, eventual!}' causing the box to leak badly. 



Another contention is that in relining there is never a good solid 

 foundation to nail to, and that the nails keep working loose and 

 catching passing timber, causing jams. It is claimed that, by the 

 use of the 1^-inch or 2-inch box lining reinforced by the battens 

 nailed on from the outside, the element of "spring" is materially 



reduced. 



ADVISABLE METHOD OF NAILING. 



In the construction of either type of box or the nailing on of the 

 battens, the nails should, whenever possible, be driven from the 

 outside and clinched on the inside of the box with the point of the 

 nail turned down the flume. By so doing the nails become tighter 

 as the inside of the box wears, since the flumed material strikes the 

 nails and drives or draws them in harder. When the inside of the 

 box is so badly worn that it is necessary to replace the lining, the new 

 lining furnishes a solid substance through which to nail. Each style 

 of construction has its particular merits, and the prospective opera- 

 tor should decide for himself which is more applicable to his needs. 



Tables showing approximate amount of material necessary to con- 

 struct flumes of different sizes follow: 



Table 1. — Weight of water in a 16-foot section of flume when filled to various depths. 





Weight of 





Weight of 





Weight of 





water in a 





water in a 





water in a 



Slant depth. 



section of 



Slant depth. 



section of 



Slant depth. 



section of 





flume 16 





flume 16 





flume 16 





feet long. 





feet long. 





feet long. 



Inches. 



Pounds. 



Inches. 



Pounds. 



Inches. 



Pounds. 



20 



1,390 



34 



4. mo 



4S 



7,990 



22 



1,680 



36 



4,490 



50 



8, 670 



24 



2,000 



38 



5,010 



52 



9,360 



26 



2,350 



40 



5,540 



54 



10, 100 



28 



2,710 



42 



6,110 



56 



10,900 



30 



3,110 



44 



6,740 



58 



11,700 



32 



3, 560 



46 



7,300 



60 



12,500 



