Show distribution OF CHLORINE chlorine a constituent of common salt is present in nearly all natural waters it is one of the ingredients of dangerous organic matter it undergoes none of the chemical changes common to the the other component parts of organic matter and its determination furnishes reliable and persistent evidence concerning the pollution of any water A certain proportion of the chlorine in a water has its origin in natural causes and has no relation to artificial pollution it is necessary he therefore her etore in determining the character of a water tor for domestic purposes to consider this natural or normal chlorine and whenever the chlorine present is in excess of the normal the evidence of past pollution is complete A paper entitled the normal distribution ot of chlorine in the natural waters of new york and new england which the united states geological survey has just pub dished should therefore be of very practical interest to the residents of that section the original sources ot of chlorine are mineral salt deposits and finely divided s salt alt spray from the sea all salt found in waters not coming from these original sources comes from domestic drainage and indicates that the water either is at the present time polluted or was polluted and has since been purified pu rifled by a comparison of the salt content of any water under examination with the normal chlotine chloi ine lne figure for that region the extent of past or present pollution may be determined the salt spray from the sea which is the chief source of normal chlorine in natural water is blown over the land by storms and the amount of chlorine diminishes as the distance from the ocean increases this decrease is so definite nite that equal amounts of chlorine are found along lines generally parallel to the seacoast thus affording a basis for the establishment of in massachusetts and connecticut these lines have been located and for several years the information has proved to be of great value to the water supply interests of those states the present paper which was prepared by mr daniel D jackson extends this information to the remainder of the new Eli england gland states and to new york mr jacksons report contains chlorine determinations for maine new hampshire vermont massachusetts rhode island connecticut and new york with a description of the methods of procedure used in the determination of chlorine and five normal chlorine maps having a map of this character for any coast st state a te we are then able to estimate the pollution in any natural water by the amount of chlorine present in excess of the normal quantity in some instance it is first necessary to ascertain that the chlorine is not derived from mineral sources the normal chlorine lines are of great practical value both to the chemist and to the engineer as they give an index from which may be estimated the sanitary qually of most waters analyzed within the coast states the chlorine also furnishes information as to the source of deep seated springs or artesian wells those desiring copies of mr jacksons report should apply to the director of the united states geological survey washington D C they will be furnished free of charge the report is listed as water supply and irrigation paper no among the surveys publications |