u. 17 '/•;/»' I'OLurios 



Gathering Driftwood from the polluted waters about the Battery. 



One of the ways by which typhoid fever is spread. 



One of a series of models illustrating the danger from impure water. 



imporvious to wator-bearing strata shows how p;round-water suppUes are 

 ol)taiiied. A series of samples and models illustrate the variations in 

 composition which occur in natural waters, from the swamps of Virginia 

 to the deep wells of Iowa and the turl^id rivers of the Ohio valley. 



Some of the principal micro-organisms, Algie and Protozoa, which 

 grow in reservoirs and impart tastes and odors to water are represented 

 by a series of glass models. The effect produced by the pollution of 

 water by disease germs is illustrated by relief maps and diagrams show- 

 ing the course of famous typhoid and cholera epidemics. Models are 

 displayed which illustrate the purification of water by storage, filtration 

 and disinfection, the filter model being an elaborate representation of the 

 ])hint at Little Falls, X. J. Diagrams and models indicate the results of 

 water purification as measured both in dollars and cents and in the sav- 

 ing of human life. Finally a series of five large relief maps shows the 

 growth and devel()])ment of the water supply of New York City. 



Following the water-su]^])ly exhibit is a series of models illustrating 



the dangers from improper disposal of the liquid wastes 



„., „, , of the citv and how thev mav be avoided. Actual points 



City Wastes • . ' * . . 



of <lang(M- in the neighl)orhood of New York are sliown 



where polluted harbor waters. i)atliing places and shell-fish beds are a 



