DEVICES, APPLIANCES AND CONTRIVANCES. 405 



which to build the dams, which is a point of impor- 

 tance to farmers who take pride in keeping their ditches 

 in good condition. The materials for a common apron, 

 such as is shown in Fig. 96, aside from the canvas, are 

 a piece of scantling seven feet long, two laths, a bit of 

 sheet iron, a piece of rope and a few short nails. The 

 canvas should be twelve-ounce, and for fifty-inch 

 ditches and upward should be sixty inches in width, 

 so as to afford ample prote(5lion for the sides of the 

 ditch. Nail the scantling to the canvas through the 

 lath, and to the bottom of the apron fasten in the same 

 way a piece of i x 

 3, fifteen inches in CI 

 length. Put a rope 

 handle in the scant- 

 ling, and a strong 

 wire staple in the 

 piece fastened to the 

 bottom of the apron. 

 When set, one end of 

 the brace engages 

 this staple and the other end the rope handle. For 

 laterals of ordinary depth the apron should be three 

 feet long, to allow the canvas to lie on the bottom of 

 the ditch for a few inches behind the staple; otherwise 

 the water will cut under and escape. Make the brace 

 similar to the one shown in the sketch, and cut to 

 suitable length to allow the canvas to lie on the bot- 

 tom of the ditch. 



The Tri-Lateral Canvas Dam. — It will be seen 

 that the essential feature of this dam will admit of 

 varied construdlion in its attachments. A cheap and 



FTG. 96 — THE APRON DAM. 



