FILTERS. 123 



Other hose extending downward to the different apartments of 

 the building. The convenience of this arrangement for the 

 supply of rain-water in the rooms, and also for extinguishing 

 fire, must be apparent. See plate , fig. . 



FILTERS. 



Perforated caoutchouc ivory and whalebone are suitable 

 materials for the strainers of filters, or the filters may be made 

 wholly of these materials instead of metal. Fig. , plate , 

 represent a filter of this kind attached to a flexible water reser- 

 voir of gum-elastic. 



