736 SKC. 15. GEOGRAPHY. 



3011. Hydra Weight Detaching Apparatus ; date 1868. 

 By Gibbs, Artificer, H.M.S. " Hydra." Used in sounding Atlantic 

 and 'Indian Oceans. 



The wooden models represent (exact size) iron sinkers, each of one hundred- 

 weight ; they are suspended on the sounding tube by the iron ring and wire, 

 to a button which protrudes through a steel spring on the sliding rod above, 

 the spring being kept back by the weight of the sinkers. On reaching sea 

 bottom and the sounding line slackening, the rod slides down, the sinker 

 weights then resting, the steel spring throws the suspending wire off, and the 

 weights are left behind as the tube is drawn through them. A butterfly valve 

 within the tube at the bottom secures a portion of the sea bottom. 



3012. Baillie Weight Detaching Apparatus; date 1872. 

 By Navigating Lieut. C. W. Baillie, R.N. In general use in 

 H.M.S. "Challenger." 



Iron sinkers of half a hundredweight each (exhibited in wood models) in 

 numbers sufficient for varying ocean depths, are placed on the sounding tube 

 and suspended by the ring and wire to two shoulders that project from the 

 sides of a sliding rod working in the upper part of the sounding tube. On 

 touching sea bottom and the sounding line slackening, the sinker weights 

 draw the sliding rod downwards, and the shoulders passing within the sounding 

 tube, the wire is thrown off, and the weights released. The lower portion of 

 the tube, to which a valve is attached, receives the specimen of the sea bottom. 



3013. Hurt's Bag and Nipper, for sounding in moderate 

 depths without stopping the ship's way. Invented by Mr. Gould, 

 an American (about 1812). 



The bag is first soaked in water to render it air-tight, and when used is in- 

 flated ; a wooden tube and peg is affixed for the purpose. The sounding line 

 is placed in the nipper or snatch attached to the bag, and on the sounding lead 

 being cast from the ship, the whole is thrown overboard, the inflated bag 

 floating as the line runs through the attached nipper, the bag keeping 

 immediately over the descending lead. 



On the lead reaching the bottom, indicated by the spring of the bag, no 

 more sounding line will pass through the nipper, and the place where it is thus 

 nipped is the vertical depth of water as marked on the line. 



3014. Massey's self-registering Sounding Machine ; date 

 18GO. Adapted for moderate depths. In use in H.M. Navy. 



3015. Ericsson's self-registering Sounding Machine 5 date 

 1836. For sounding in moderate depths. 



This instrument records the vertical depth irrespective of the amount of 

 sounding line thrown out from the ship. 



The depth is ascertained by the compression of air within a glass tube, the 

 value of the compression, in accordance with depth, being recorded by the 

 quantity of water passing into the tube as the air is compressed, and a scale 

 adapted to it. 



3016. Cup Lead. For sounding in depths not exceeding 

 1,000 fathoms, and to procure specimens of the sea bottom (about 

 1858) ; model. Originally used in sounding North Atlantic. 



