218 



'lEE DEPTHS OF THE SEA. 



[chap. v. 



apparatus is so adjusted, that when 

 the weight is attached and the instru- 

 ment hanging ready for use, as repre- 

 sented in the figure, the rod f main- 

 tains a horizontal position. When the 

 instrument strikes the ground, the 

 tension on the bar p is relieved, the 

 weight draws the rod d off the claw 

 and slips off, at the same time filling 

 the scoop. When hauling up, all the 

 instrument falls into a nearly vertical 

 line, and the scoop comes up full in 

 the middle, the weight of d keeping 

 its mouth closed up against its lid. 



The apparatus used during the 

 cruise of the 'Porcupine," where 

 sounding was carried on to the utmost 

 attainable accuracy and at great 

 depths, was a somewhat elaborate 

 modification of Brooke's sounding 

 machine which had been previously 

 employed by Captain Shortland in 

 the voyage of H.M.S. ' Hydra,' sound- 

 ing across the Arabian Gulf prepara- 

 tory to laying the Indian Cable. 



This special modification, which cer- 

 tainly answered remarkably well, ap- 

 pears to have been due entirely to 

 Mr. Gibbs, the blacksmith on board 

 the vessel.^ We christened it the 



' Sounding Voyage of H.M.S. ' Hydra,' Captain 

 P. F. Shortland, 1868. Published by order of the 

 F'»- *2r''^'l? 'Hydra' j^oydg Commiss. of the Admiralty. London : 1869. 



Sounding Machine. ^ 



