II. HYDROGRAPHY. 735 



3005. Brooke's Hod, for bringing up specimens of the sea 

 bottom, and weight detaching apparatus (about 1856). By Mr. 

 Brooke, Midshipman, United States Navy. Used, with various 

 modifications, to 1868. 



In the first instrument employed in the United States Navy the valve 

 securing the specimen of the sea bottom was not applied, quills being inserted 

 in the tube for that purpose. The hook, with the wire and ring, supports the 

 sinker weight as long as there is strain on the sounding line ; the moment 

 that strain ceases by the rod touching sea bottom, the sinker weights turn 

 the suspending hook and the wire being released, the sinkers slide off as the 

 rod is drawn upwards. 



3006. Brooke's Hod, another mode of detaching sinker 

 weights ; date 1857. Used in sounding North Atlantic. 



3007. Skead's Weight Detaching Apparatus ; date 1857. 

 By Mr. F. Skead, Master R.N., H.M.S. " Tartarus." Used in 

 Mediterranean Sea survey. 



A 68-lb. shot (represented by the wooden ball, exact size) is slung with 

 wire, and the detaching apparatus attached. On reaching sea bottom, the 

 small weight on the apparatus, which had till this time been kept above the 

 hook by the weight of the shot, is freed, and, falling, reverses the hook ; 

 the shot is thus left behind. The small weight is roughed to secure a small 

 portion of the sea bottom. 



3008. Bonnici's Weight Detaching Clam ; date 1857. 

 By Mr. C. Bonnici. Used in Mediterranean Sea survey. 



A 68 Ib. shot (represented by the wooden ball) is slung with wire, and the 

 claw attached, the weight of the shot preventing the claw opening. On 

 reaching sea bottom and the line slackened, the arms of the claw fall by their 

 own weight, and the sinker is released. 



3009. Bulldog Clam, for bringing up specimens of the sea 

 bottom ; date 1860. Used in H.M. ships " Bulldog " and " Por- 

 cupine," North Atlantic Ocean. 



The claw is kept open by a tubular sinker weight, resting on the four 

 horns. When the weight is detached on reaching sea bottom, the india- 

 rubber bands contract, closing the claw, and thus securing the sea bottom 

 contained within it. 



3010. Fitzgerald Sounding Machine, combining appa- 

 ratus for detaching the weight and procuring specimens of the sea 

 bottom; date 1867. By Lieutenant Fitzgerald, R.N., employed 

 in H.M.S. " Cordelia," in deep sea sounding between Jamaica 

 and Cuba. 



An iron sinker weight (represented by wood model) is hooked to the side 

 of the sounding bar, and the hook or lever, to which the sounding line is 

 attached, is inserted in the hole at the upper end of the bar. When suspended, 

 the weight of the sinker keeps the lever in the hole and the bar nearly 

 vertical. On reaching sea bottom, the scoop is driven, into the ground, and 

 the hook being freed by the slackening of the sounding line the weight falls 

 over ; the action of hauling in the sounding line reverses the bar, unhooks 

 the weight, and the scoop closes with its contents. 



