FIG. I.-CURVES SHOWING THE PARALLELISM BETWEEN TURBIDITY AND 
■NUMBER OF BACTERIA PER CUBIC CENTIMETER IN THE SEVERAL RES- 
ERVOIRS. (See Page 286.'» 
AVERAGE NUMBER OF BACTERIA PER C. C. -4 
AVERAGE TURBIDITY ^4 
'HE NORRIS PETERS CO.. ViASHJNCTON. D. C. 
