ig PROCEEDINGS S. i. ASsV ARTS AND SCIENCES. [VoL. I 



If the waters affected by the salt deposits in the western part of New 

 Vork State be disregarded, it has been found that in the coast States the 

 chlorine in the natural waters is practically all brought in by the sea 

 winds and that the amount constantly diminishes as the distance from 

 the coast increases. By connecting the localities where analyses of the 

 waters show equal amounts of chlorine a series of isochlors are estab- 

 lished, which on a map of the region are indicated by a series of lines, 

 roughly following the contours of the coast line and located further and 

 further apart as the distance from the coast line increases. When we 

 know in this way the normal amount of chlorine which should be pres- 

 ent in the water at any locality, any excess which may be found is a clear 

 indication of some local conditions which cause the excess, and the 

 identification of such local conditions is often of the highest importance, 

 for the reason that an excess of chlorine may mean organic pollution 

 of the water and be an indication that it is unfit for domestic purposes.- 



The mere presence of an excess of chlorine, however, does not necessari- 

 ly indicate such pollution but may be due to the presence of natural 

 salt deposits in the ground or to seepage from the ocean, so that each 

 locality should be made the subject of an independent investigation. 



By consulting the isochlor map of New York (pi. v) it may be 

 seen that Staten Island is located within isochlor 6.0, or in other words 

 that the normal amount of chlorine in our natural waters should be 

 six parts per million. On page 30 are given the results obtained from 

 analyses of several Staten Island waters, as follows: 



"Clifton, water supply - .-• 6.0 



Richmond Turnpike station. Crystal Water Supply Company 6.2 



Stapleton, water supply < 6.0 



Tottenville, water supply. 6.0" 



These results are of interest as indicating that so far as the water 

 from these sources of supply is concerned the amount of chlorine 

 present is normal or so slightly in excess that the excess may be dis- 

 regarded. 



It is unfortunate that analyses of the water from the Staten Island 

 Water Supply Co. were not included, as these would have afforded 

 interesting comparisons. We are, however, able to quote several 

 from other previous reports, a number of which have been given 

 in papers read before the Natural Science Association of Staten Island 

 from time to time and printed in the Proceedings , Vol. iv, Feb. 9, 

 1895, p. 61; Vol. viii, Dec. 13, 1902, p. 45. From the above mentioned 

 sources of information the following data have been abstracted: 



