22 CAPE COD CBANBEEBIES. 



the dam in the spring than in the fall, for this reason. 

 The walls, or sides of the dam should gradually taper 

 from the foundation to the top, so that, starting with a 

 width of twelve feet at the bottom, it will be nine feet 

 wide at the top, and will be suitable for a driveway in 



Fig. 8. — SECTION OF DAM. 



crossing the bog. Figure 8, showing a section of the 

 dam, will give an idea of this method of structure. 



THE ELUME. 



The flume should be constructed and set as near the 

 center of the dam as convenient. In case the bog is sup- 

 plied with water from a flowing stream or river, the flume 

 will of course be placed in the bed of that stream or river. 

 Having set the flume, the dam is built up to it. The 

 flume is constructed as follows : The frame is made of 

 cedar or cypress timber, about eight inches square, and 

 the stuff for planking is of two-inch cypress or pine. For 

 a dam of twelve feet foundation, the flume would require 

 a frame of corresponding length and width. The frame 

 is made for the bottom and sides as shown in figure 9, 

 and the planking is spiked to this frame on the inside ; 

 previous to which, however, piles of matched spruce 

 boards are driven the whole width of the flume across the 

 center. These piles are of one-inch boards, and are 



