Report of the Board of Shell Fish Commissioners 47 



torn at a flag buoy which has been dropped by the local oyster- 

 man and located by the hydrographic engineers. It is then 

 towed by the launch in a definite direction by means of a 

 range on shore, and its position when taken from the bottom 

 is located by the person in charge of the examining boat by 

 means of a set of sextant angles. The distance between the 

 positions at either end of the line covered by the dredge is 

 measured on the chart. The number of oysters per square yard 

 on the area examined is found by dividing the total number of 

 oysters caught by the total number of square yards covered. 



