OYSTER CULTURE IN AMERICA. 837 



and high water will indicate the approach of easterly 

 weather. 



The average of the density determinations 



taken at twenty-three different points west, but within five 

 miles of the Bluff Shoal, gives 1.0106 as the specific gravity 

 of the water of the area. 



The average of the determinations taken at twenty- 

 two different points east, and within five miles of the Shoal, 

 gives 1.0125 as the specific gravity of that area. 



In other words, east of the shoal the specific gravity is 



0.0019 higher than west of the shoal The 



difference in the character of the water is apparently due 

 to the difference in origin of the water on the east and 

 west sides of the shoal that on the east coming from 

 Albemarle, and being influenced by the tidal currents of 

 the inlets, while that on the west is from the Pamplico and 

 Neuse Rivers, and is not subjected to any oceanic influence. 

 . The study of the specific gravities of water 

 offers an interesting field for investigation at all times, but 

 in the figures given below the object is the determination 

 of the average specific gravity of the areas, and the amount 

 of variation in " a general summary of the results of all 

 observations, arranged by 27 sections and by counties," of 

 which the following are the totals : 



SUMMARY BY SECTIONS. Area in acres, 1,325,419. 

 Area upon which oysters can be grown, 756,520. Average 

 specific gravity, varying from 1.0040 to 1.0230, averaging 

 about i. 01 12. Extreme depths of water, i to 28 feet, aver- 

 aging about 1 2 feet. General character of bottom : 7 

 being spoken of as sand, 14 sand and mud, and 6 mud. 



SUMMARY BY COUNTIES. Area in acres : public 

 grounds, 20,553.11 ; natural beds, 8,327.90 ; suitable ground 

 (approx.), 583,330 ; available for entry (approx.), 502,000. 



