4 BULLETIN 57, U. S. DEPARTMENT OF AGEICULTUEE. 



eartli or sand and lay the concrete and reenforcing on this cone. 



Allow it to set and harden well before removing the forms and earth. 



The followmg table gives an approximate bill of materials for two 



sizes of cisterns: 



Cisterns- — Material. 



[Concrete: 1 part cement, 2J parts sand, 5 parts gravel.] 









14 feet 



ISJ feet 









deep 



deep 









(10-foot 



(10-foot 









cvlinder. 



cylinder. 









4-foot 



3.',-foot 





Material. 





cone), 

 8 feet in 

 diameter, 

 capacity 



3,800 

 gallons. 



cone), 

 6 feet in 

 diameter, 

 capacity 



2,100 

 gallons. 



Cement 





bags.. 



43 



31 



Sand 





cubic yards. . 



4i 



3 



Gravel 





do 



9 



1,000 



225 



6J 



Brick for filter wall. . . " . - 



800 



Lumber for forms 





board feet _ 



200 







The OfRce of Public Roads of this department has established a 

 method of making concrete by intermixing mineral residuum oil, 





Fig. 2. — Crib of brick or stone for intake from pond. 



which, according to theii- tests, makes a damp-proof and fairly 

 water-tight concrete. Information may be obtained by writhig to 

 that office for then- bulletin on oil-mixed Portland cement concrete.^ 



If water is piped from a stream or pond subject to pollution, the 

 pipe entrance should be placed in a crib and screened, as shown hi 

 iigure 2. The pipe can then empty mto a receiving filter, made of 

 concrete, which contains fine sand, gravel, and powdered charcoal 

 in layers (fig. 3), and from which it empties into the cistern. The 

 rain-water pipe from the eave trough should be provided with a 

 switch or cut-ofi", so that the flow may be diverted to the outside — 

 as, for instance, for a short timt; at the beginning of rains^ — to exclude 

 the filth collected on the roof and gutters. An overflow pipe should 

 be provided in the side of the cistern and should be screened to 

 exclude rats and other vermin. 



»U. S. Dept. Agr., OflBce Pub. Roads Bui. 46. 



