CISTERNS AND TANKS. 



33 



A mill with arms six feet long may be made to do work 

 equal to one-fourth of a horse-power, if all the working 

 parts are well fitted and kept well lubricated, as all 

 machinery should be. When out of use, the sails are un 

 tied and removed, or they may be furled and clewed to 

 the arms until again required. 



A one-horse railroad-power would also serve a useful 

 purpose in raising water from wells into an elevated res 

 ervoir, where it could be stored for use. For small 



Fig. 2. SQUARE TANK. 



gardens the water from the roofs of buildings may be 

 collected in tanks or cisterns raised a few feet above the 

 level of the ground. 



A round tank, hooped with iron bands, 12 feet deep 

 and 15 feet in diameter, will hold over -15, 000 gallons. A 

 square tank (fig. 2) may be made of jointed and matched 

 planks, which are forced closely together by wedges, act 

 ing upon a timber frame which encloses the planks. This 



