5 \^\^ 



PROCEEDINGS 



OF THE 



AMERICAN PHILOSOPHICAL SOCIETY 



HELD AT PHILADELPHIA 

 FOR PROMOTING USEFUL KNOWLEDGE 



Vol. L September-December, 1911 No. 201 



AN HYDROMETRIC INVESTIGATION OF THE INFLU- 

 ENCE OF SEA WATER ON THE DISTRIBUTION OF 

 SALT MARSH AND ESTUARINE PLANTS. 



(Plates XX and XXL) 

 By JOHX W. HARSHBERGER, Ph.D. 

 (Read April 23, 19 lo.) 



Elsewhere^ I have discussed the general character of the vegeta- 

 tion of the salt marshes of the northern New Jersey coast and the 

 factors controlling the distribution of marsh plants in that area. 

 This earlier study was based largely on physiographic and floristic 

 considerations, although reference is made on page 379 of that paper 

 to the use of the hydrometer in the investigation of the actual influ- 

 ence of sea water, or salty soil, on the distribution of a limited num- 

 ber of plants. The investigation begun in 1909 has been continued 

 until sufficient facts have accumulated to warrant their publication. 



The use of a special kind of hydrometer was suggested as a 

 simple but efficient method of investigating the salt content of salt 

 marsh soils and of the estuarine water which, at first strongly saline, 

 becomes largely diluted, as it mingles with that of streams flowing 

 in a seaward direction. This is the first actual use of the hydrometer 



^ Harshberger, John W., " The Vegetation of the Salt IMarshes and of 

 the Salt and Fresh Water Ponds of Northern Coastal New Jersey," Pro- 

 ceedings Academy of Natural Sciences of Philadelphia, 1909, 373-400, with 

 6 figures. 



PROC. AMER. PHIL. SOC., L. 20I EE, PRINTED AUG. 25, I9II. 



457 



