STORAGE AND DISTRIBUTION. 



139 



way, the most usual being on a brick or stone 

 tower by means of cross joists of one section laid 

 across it. It may simply rest on a flat roof, pro- 



FIG. 102. 



vided this is quite strong enough to carry the tank 

 when full. In other cases a system of cast-iron pillars 

 may be used, as shown by fig. 102. 



