KINDS OF TROUGHS 301 



Circular troughs, constructed of narrow staves of wood bound 

 together by steel rods are probably the most common on farm 

 pastures. The steel rods or hoops, three or four in number, 

 when properly spaced, are drawn tightly about the stave con- 

 struction, and after a few tightenings the tank becomes im- 

 pervious to water. These troughs are ordinarily 6 to 14 feet 

 in diameter. The chief objection to this type of trough is the 

 shrinking of the staves when the tank is empty. 



Metal, Cement, and Other Troughs. — After all is said and done 

 the familiar metal trough is generally superior to any other type. 

 Such a trough can be purchased in almost any part of the coun- 

 try. Either it may be received ready to place, or it may come 

 " knocked down." The most popular form of metal trough is 

 half-round in shape and well supported by heavy bands, usually 

 with a wooden rim about the top. Metal troughs are little 

 more expensive than the stave troughs of equal capacity, and 

 they last much longer. 



If sand and gravel are readily available, and the cost of ce- 

 ment is not excessive, concrete is excellent material for trough 

 construction. Properly constructed cement troughs are prac- 

 tically indestructible. It is necessary, however, to locate the 

 cement trough permanently, as it cannot easily be removed to 

 another locality. In the construction of cement troughs it is 

 important that the sides and bottom, and especially the corners, 

 be well reinforced with iron rods or heavy wire netting. In 

 finishing the trough, the inner and outer surfaces should be 

 covered with a very rich mixture of sand and cement or of pure 

 cement. This is important in order to close small cracks and 

 seams. 



Troughs constructed of dirt in the form of small reservoirs 

 are wasteful and generally unsatisfactory. From the very 

 construction of such troughs it is evident that loss through 

 evaporation and seepage is great. Moreover, the water is 

 always impure. As these troughs cannot well be cleaned, their 

 condition grows worse from year to year. 



Trough Foundation. — The life of any form of trough is 

 largely determined by its foundation. Cement or rock sup 



