14 



THREE CRUISES OF THE "BLAKE. 



U. S. Coast Survey Steamer " Blake." Locality, off Grenada. Date, March 2, 1879. 

 Sounding No. 37. Line K. Sinker used, lead ; weight, 34 lbs. 



Reading of Register 875 turns. 



Correction for stray line 6 



Correction for turns of wire 74 



Correct depth 955 fathoms. 



The time occupied in taking one of the most recent deep- 

 sea soundings by the old methods (those of the "Challenger") 

 is here given to show the comparative advantage of the two. 



Hydra machine, weight 336 lbs. Weight of line, 12 lbs. 8 oz. per 100 fms. ; breaking 

 strain, 1,200 lbs. ; circumference, 0.8". 



The whole time occupied in descent was thirty-three minutes, 

 thirty-five seconds ; and in heaving up, two hours, two minutes ! 



