CANAI, CONSTRUCTION. 8 1 



able to withstand all the strain that will be put upon it. 

 The cement is mixed with clean sand in the proportion 

 of one barrel of the former to four barrels of the latter. 

 For a canal carrying 3,500 cubic inches of water, with 

 a bottom 8 feet wide and sides 4 feet high, it requires 

 2,000 barrels of cement for 7 miles of length. The 

 work of laying the cement is done very rapidly and 

 thoroughly. Along the edge of the canal a small pipe 

 is laid, through which a steam-pump forces the water 

 which is used in keeping the earth wet and in mixing 

 the mortar. At regular intervals are placed piles of 

 sand and barrels of cement. A mixing-box on wheels 

 with a trough running down into the canal is run on 

 the top of the bank, and the plasterers take from this 

 and cement the sides. This is moved along as fast 

 as needed, thus saving the use of wheelbarrows. Fol- 

 lowing comes another mixing-box on wheels in the 

 bottom of the canal, and from this the mortar is taken 

 to cement the bottom. The work should be allowed to 

 stand for a time so as to thoroughly dry before water 

 is turned in. 



Building the Laterals. — In constru(5ling the sup- 

 ply laterals leading from the main canal to the farm, 

 the walls should be built up so that the bottom of the 

 lateral may be higher than the surface of the ground. 

 This is vital to the economic use of water. The laterals 

 can be construdled in the loose soil on the farm for the 

 reason that the water is desired to soak into the ground. 

 The laterals may be changed every time water is put on 

 the land, for the reason that always as soon as possible 

 after irrigating, the ground should be cultivated, thus 

 obliterating the lateral and preventing the soil from 



