DEVICES AND APPLIANCES. 277 



The Tri-Lateral Canvas Dam. It will be seen 

 that the essential feature of this dam will admit of 

 varied construction in its attachments. A cheap and 

 simple method of construction would be to nail one of 

 the three borders to a pole, and make a loop by means 

 of a stout cord, in the opposite corner. A better con- 

 struction, however, is recommended. Select a stout stick 

 of hard wood, or good pine 2x4 and six feet long, bore 

 a one-half inch hole through the center of the larger 

 diameter about one foot from the two ends, and make a 

 wide saw cut between and connecting the two holes. 

 The cut may be started with a keyhole saw. Make the 

 sides of equal length, 

 about four feet and 

 four inches. Hem 

 the edges so as to ad- 

 mit the passage of a 

 half-inch rope around 

 the entire border 

 between the two lay- 

 ers of cloth. To fas- 

 ten the cloth to the 

 stick, pass one edge 

 of the canvas through 

 the saw kerf to the opposite edge, then thread the rope 

 through the half-inch holes in the stick and around 

 through the border of the canvas, remembering to pass the 

 rope through a two-inch iron ring at the angle opposite 

 the stick, for a fastener or anchor in the ditch. The 

 two ends of the rope should be made to meet about half- 

 way along the edge of the stick. Bolt or nail through 

 the flat side of the stick to prevent the sides from spread- 

 ing and the canvas from slipping in the kerf. The other 

 two edges should be fastened firmly to the rope by sew- 

 ing a stout cord around the rope and canvas. To make 

 the whole thing complete, a half-inch rod of iron about 



