CONSTRUCTION TANKS AND POOLS 219 



are rabbeted to y^-mch. depth and Ij-^ inches from edge to receive the 

 ends. Bottom boards are tongued and grooved. All joints should 

 receive a preliminary coating of white lead paint. After this is dried, 

 a thicker coat should be applied just before putting joints together. 

 The tank is then clamped and 1%-inch screws inserted through the 

 sides into the bottom and ends, and through the bottom into the ends. 

 Cleats 3 inches wide are placed across centre of bottom and all the 

 way around the ends. Through the top of latter is passed an iron rod 

 J4 inch thick, then secured and tightened with washer and nut at ends. 

 The smaller tank is constructed in the same manner, except that cleat 

 across centre bottom and the iron rods are omitted. 



While painting the outside improves the appearance, it has more 

 of a tendency to rot a tank than preserve it, as the paint prevents the 

 evaporation of the moisture naturally gathered from the inside. 

 Leaks will usually correct themselves in a few days, but should they 

 not do so, a few handfuls of earth stirred in the water and allowed 

 to stand several hours or days will make the job tight. Occasional 

 stirring of the dirty water helps. The white lead should be allowed 

 a day to harden before filling with water. 



CONSTRUCTION OF TANKS AND POOLS 



For outdoor purposes it is better to dig holes in the ground and 

 puddle them with clay rather than make poorly-constructed concrete 

 basins or pools of any size. Unless the work is properly done, the 

 frost is certain to crack it, and even the weight of the water may be 

 sufficient to bring about this result. Repaired work is never satis- 

 factory, and the next winter will open more seams, making continual 

 expense, dissatisfaction, loss of water and of fishes. With indoor con- 

 crete tanks, too, thorough construction is a good investment. 



The main points in the construction of such work are good foun- 

 dations, thorough reinforcement, good cement properly mixed, and 

 one continuous job for the finishing coat. The concrete centre ought 

 also be poured within the space of one day. There is some difference 

 of opinion as to the necessity for a base of cinders. The author 

 favors them. If used, they should be the hard kind, wetted down and 

 packed solid to a depth of one foot or more. For tanks of moderate 

 size — say 11 x 22 feet — reinforcement should be by use of ;^-inch steel 

 rods, crossed on squares of 8 inches. The bottom needs two layers 

 of these bars, one near the upper and one near the lower surface. This 

 protects against both inside and outside pressures. The lower frame 

 of bars is bent up at the ends to form a cradle, thus reinforcing the 



