644 SEC. 15. GEOGRAPHY. 



3142. New Lead for Deep-sea Soundings ; invented by 

 Francis Hopfgartner, Austrian Imperial and Royal Naval Officer 

 of the Line, and Moritz Arzberger, Civil Engineer at Vienna. 



Lieut. Hopfgartner and Moritz Arzberger. 



The exterior form of this apparatus is that of a tube, of which the lower 

 part forms the contrivance for throwing off the weight, while the centre part 

 contains the indicating apparatus, being a system of metal cases which, through 

 the pressure produced on them by the water, indicate the depth on a scale. 

 The upper part is an arrangement for propelling the apparatus upwards in 

 case the lead is to be used without a line. 



r 3 142 a. Sinker and Tube with Detaching Appliance for 

 Sir William Thomson's Pianoforte Wire Sounding 

 Apparatus. Sir William Thomson, F.R.S. 



The pianoforte wire (No. 22 B. W. G. Webster and Horsfall's) weighs about 

 14^ Ibs. per nautical mile (6,086 feet) in air, or 12| Ibs. in water. 



The strength of this wire to resist pull is such that it bears about 230 Ibs. 

 (104 kilogrammes) weight in air, or 29'4 kilometres (or 15'9 nautical miles 

 of its own length). 



The splice, a specimen of which is shown, is made as follows : The two 

 pieces of wire to be spliced are first prepared by warming them slightly, and 

 melting and coating of marine glue to promote surface friction. About three 

 feet of the ends so prepared are laid together and held between the finger and 

 thumb at the middle of the portions thus overlapping. Then the free foot 

 and a half of wire on one side is bent close along the other in a long spiral, 

 with a lay of about one turn per inch, and the same is done for the free foot 

 and a half of wire on the other side. The ends are then served firmly round 

 with twine, and the splice is complete. 



To the lower end of the wire a ring weighing about ^ Ib. is attached, and a 

 chain of two fathoms long, weighing 3 Ibs., is shackled to this ring. The 

 lower end of this chain bears an elastic wire double claw. The weight is 

 spherical, with a perforation for the tube and two indentations for the two 

 claws, by which it is hung till it reaches the bottom. The moment its weight 

 is taken off by the bottom and removed from the claws, they spring out and 

 leave it free ; but before this is done it presses the tube into the ground by 

 means of a bolt attached to the tube. This bolt is kept by a slight spring in 

 its place until the wire is hauled up. During the time the wire is going down, 

 the tube is kept from falling by this bolt, which after the tube touches the 

 bottom, presses it downwards into the mud. When the wire is hauled up, a 

 piece of small cord two or three inches long, connecting the lower end of the 

 chain with a lever arm belonging to the bolt, which was loose so long as the 

 weight hung by the claws, becomes tightened and draws out the bolt. This 

 leaves the tube free to come away from the weight, and it is drawn up by the 

 cord, chain, and wire. 



Two specimens of the apparatus are exhibited, one showing the weight 

 hanging on the claw with the tube resting on the bolt just before touching the 

 ground ; the other showing the weight supported partly by the bottom and 

 partly by the tube pressed into the bottom supposed to be mud, and the cord 

 scarcely yet tightened enough to draw out the bolt. 



3 142 a. Ship's Sounders. L. Casella, 



