28 



found in the upper part of Fishing Bay, with the tide three-quarters ebb. The following table 

 shows the maximum and minimum density on each bed, with state of tide and remarks : 



Comparison of densities — Tangier. 



[The figures represent the excess of density over that of distilled water, which is represented as 1.000.] 



Bed. 



Max. 

 density. 



Tide. 



Remarks. 



Diff. 



Min. 



density. 



Tide. 



Remarks. 



Fishing Bay 



Were Point 



Shark's Fin..~ 



Xanticoke M. G 



Clump Point 



Horsey's Bar 1 



Tyler's Rock 



Drumming Shoal .... J 



Grass Tangier 



•Turtle Egg Rock 



Chain Shoal 



Mud Rock 



Muscle Hole 



Piney Island Bar 



Manokin River 



Big Annemessex 



Harris Rock 



Terrapin Sands 



Rock oft' Jane's Island 



Great Rock 



Woman's Marsh 



1. 0136 

 1. 0139 

 1. 0143 

 1. 0136 

 1. 0118 



High water 



J flood 



High water 

 High water 

 I flood 



Southern part 0025 



In channel to Hooper's Straits.. .0022 



Edge of main channel 0025 



West of channel 0017 



l.olll J and J chh . Extreme northern part. 



1.0117 Low water.. 



1.0118 | ebb Middle of bed. 



1. 0119 J ebb Middle of bed. 



Only one specimen Xo specimen. 



1. 0132 | J ebb ' Only one specimen . 



Little Thoroughfare 

 Great Thoroughfare . 



California 



Johnson's Rock 



Oak Hammock 



1. 0144 

 1. 0120 

 1. 0145 

 1. 0144 

 1. 0157 

 1. 0150 

 1. 0152 

 1. 0151 

 1. 0153 

 1. 0159 

 1.0156 

 1. 0159 

 1. 0160 



1. 0158 

 1. 0157 

 1. 0164 

 1. 0161 

 1. 0160 



£ flood ' In the chanuel . 



J flood I 



i flood | 



Jflood i 



iebb ] 



i ebb 



Iebb 



High water 



J ebb 



| ebb 



J ebb 



i flood 



febb 



. 0012 1. 0120 i flood Only one specimen. 



.0024 1 1.0120 Low water.. Middle of bed. 



South of beds 



Lower beds 



Western beds 



Southern beds 



Strong southerly winds. 



|ebb 



J flood, | ebb 



J flood 



Jflood 



iebb 



Opposite opening between Tan- 

 gier and Smith's Island. 



.0022 

 .0008 

 .0012 

 .0019 

 .0014 

 .0007 

 .0007 

 .0015 

 .0013 

 .0011 



.0016 

 .0009 

 .0005 

 .0012 

 .0013 

 .0002 



1. 0123 

 1. 0136 

 1. 0145 

 1.0131 

 1. 0128 

 1. 0144 

 1. 0146 

 1.0144 

 1. 0143 

 1. 0148 



1. 0144 

 1. 0151 

 1. 0152 

 1. 0152 

 1. 0148 

 1. 0158 



| flood 



Iebb 



Low water. . 



i ebb 



J ebb 



iebb 



High water. 



i flood 



| flood 



High water. 



| flood . 

 { flood . 

 1 flood . 

 £ flood . 

 i ebb . . 

 J ebb . . 



Middle of bed. 

 Upper beds. . 

 Eastern beds. 



Light southerly breeees. 



*A11 specimens taken on flood. This is minimum density. 



By consulting the table it will be seen that the state of the tide has but little influence upon 

 the density, though the depth of the water has, and the prevalence of strong winds may increase 

 or diminish it. There is shown a gradual and constant increase of density as the southern portion 

 of the Sound, where it opens upon the Chesapeake, is approached. There is also an increase of 

 density when in the vicinity of the openings into the bay, and a decrease in the various rivers and 

 off their mouths. 



Though the density of the water increases, yet the difference between the maximum and 

 minimum density steadily decreases to the southward, showing that the oysters on the northern 

 beds are exposed to greater fluctuations of density, and probably salinity, than those on the beds 

 to the southward. 



There were no heavy rains during my stay in the Sounds, and the densities given therefore 

 show only the condition of the water in that respect during dry weather. I was informed that 

 there was a noticeable change in its character about the mouths of the tributaries of the Sounds 

 after a heavy rainfall, and the effect upon the oysters was also perceivable. 



The difference between the maximum and minimum density of the Sound amounts to 0.0053; 

 but the difference between the maximum and minimum density on each bed will give a more 

 correct idea of the changes to which the oysters are exposed. The greatest difference is 0.0025, 

 which occurs on the Shark's Fin and Fishing Bay Beds, and the least difference on any of the 

 main beds is 0.0009 on the Little Thoroughfare. 



It would be perhaps still more correct to divide the Sound into several parts and consider the 

 fluctuation of density over them, thereby assembling a larger number of observations. Throwing 

 out the Fishing Bay beds, which by their position are removed to a great extent from the condi- 



