FLOATING AND RAFTING 
393 
between them being filled with gravel and stone. The up- 
stream face is banked up with brush and gravel to stop leakage. 
This type is not in frequent use, although it was at one time 
common in the Lake States. 
SLUICE GATES 
Lift Gate. — This is the most common type. It is rectangular 
in shape, with two outside frame pieces 5 by 7 inches in 
Fig. 134. — The Upstream Face of a Small Rafter Dam, showing a Common 
Form of Lift-Gate. 
cross-section which are made from hardwood. Intermediate 
"starts" as these pieces are called may be used on wide gates. 
Mortises 2 by 5 inches in size are cut into the edges of the starts 
at 14-inch intervals and 2- by 5-inch hardwood slats which are 
long enough to give the required gate width are fitted into the 
mortises on opposite starts. The starts and slats form the skeleton 
frame work of the gate, and also serve as points under which the 
raising lever may be placed. Two-inch hardwood planks are 
then spiked crosswise from start to start, the ends of the planks 
being flush with the edges of the starts. Gates are made 2 inches 
narrower than the width of the sluice so that they may be moved 
easily up and down the slides. The slides are placed directly 
above one of the cross timbers in the sluice, so that there will be 
