282 TOWERS AND TANKS FOR WATER-WORKS. 



Arrived at the foundations, the sheets should be sys- 

 tematically placed, the bottom pieces and angles being near- 

 est; the top pieces, cresting, etc., furthest away from the 

 foundations. 



Upon the top or face of the foundation, it is customary to 

 place the kegs of rivets, which being of the same height, 

 make a sort of platform upon which the bottom plates may 

 be put together. 



After these have been riveted to each other and to the cir- 

 cumscribing angles which fasten the bottom and shell, the 

 tightness of the bottom is tested by pouring water upon the 

 plates. If the joints are not found to be tight, they are fur- 

 ther calked, or if the leak is due to imperfect or loose rivet- 

 ing, such rivets are cut away with chisel and sledge; the hole 

 is reamed larger and a larger rivet inserted and driven. 



Field- assembly. These preliminaries having been ob- 

 served, about the outer circumference of the foundations a 

 slight, low dam of clay puddle or even of sand is constructed ; 

 into the area so formed is then slushed or poured a rich 

 cement grout, sufficient to cover the face of the foundations 

 and deep enough to entirely cover and hide the heads of the 

 rivets upon the under side of the bottom plates. Having 

 been quickly " floated " or levelled over, the bottom of the 

 tank is lowered as rapidly as possible, by means of jacks or 

 levers. 



The separate sheets of the first ring are then set in posi- 

 tion, being temporarily bolted to place and afterwards 

 riveted. 



As each sheet is placed, the surfaces in contact, or the 

 joint surfaces, should be given another coat of thick retl lead 

 and oil, as should also the joint after riveting, that the rivet - 

 heads may be entirely covered to prevent the formation of 

 rust during construction and before the finishing coats of 

 paint are supplied. 



