INVESTIGATION OF OYSTER SPAWNING, ETC., MILFORD, CONN. 



471 



rains and with the change of tide from low water to flood. In the first instance the 

 surface was covered with a layer of water from 6 inches to a foot deep, which was 

 virtually fresh or of a low salinity of about 5 parts per niille, while that on the bottom 

 was 25 or more. In the second instance the extreme difference was due to the 



26 



LU 



^2Z 



•^20 



UJ 

 UJ 

 oc 



o 



/6 



^3 



^ 2 



d 



/2 



6 



6.0 

 1.& 

 1.6 

 74 

 7.2 

 7.0 



10 

 A.M. P.M. 



AUGU3T24.I925 



Figure 26. — Hourly changes in temperature, salinity, and hydrogen-ion concentration of the water 

 during a complete tidal cycle on August 24, 1925 



progression along the bottom of heavy, more saline water with the beginning of 

 flood tide, while that at the surface was still running at ebb or at low slack water. 

 Samples taken at such times showed a difference in salinity of from 2.5 to 3 parts per 

 mille between the surface and bottom at a depth of 10 feet. 



The range of salinity in the harbor in 1925 was from 4.5 to 28.12 per inille, while 

 in 1926 the range was from 10.48 to 28.66 per mille. At the inshore Sound Station 



