792 OYSTERS, AND ALL ABOUT THEM. 



the boats or schooner. By carrying forward our own points 

 in that manner it was possible to dispense with signals, 

 the erection of which would have occasioned much delay, 

 and the sacrifice of time and labour, to procure an unneces- 

 sary degree of accuracy. The boats then ran transverse 

 lines, more or less open, over the adjacent beds, the size 

 of the anterior angle and the length of the line depending 

 upon the supposed size and character of the bed ; our 

 general method was to work with the tide, and endeavour 

 to cross the lines as we returned over the ground. 



The " oyster pilot" was sent in one boat, and one of 

 the ship's company, who was an old oysterman, was sent in 

 the other. They were provided with poles, which were 

 marked to feet, and continually probed and examined the 

 bottom as the boat passed over the line. The depth of 

 water and character of the bottom were recorded as in 

 ordinary hydrographic surveys. The position of the boat 

 was frequently ascertained by sextant angles, but as the 

 "points" were not always well defined, two angles were 

 not considered sufficient, and angles on all prominent 

 objects were taken. Occasionally, when in proximity to 

 the schooner, mast-head angles and bearings were used for 

 ascertaining the position of the boat, and in a few cases 

 the bearing and distance of some well defined point of 

 land was estimated. 



At intervals the boat was anchored, her position fixed, 

 and specimens of oysters, bottom, and water obtained, and 

 the temperature of the air, and surface and bottom water, 

 observed ; the character of the substratum of the bottom 

 was also noted, and the set and velocity of the current 

 recorded. 



The observations for ascertaining the character of the 

 bottom beneath the surface, and those for temperature, 



