MECHANICS AND USEFUL ARTS. 73 



conical top and bottom. This cylinder is filled with a liquid, specific- 

 ally lighter than water a small orifice near the bottom allowing the 

 pressure of the water to be exerted on the inside as well as the outside 

 of the machine. To sink the machine two cannon-balls are attached ; 

 and when it arrives at the bottom, a stop, projecting below the cannon- 

 balls, is forced upwards and disconnects them. The machine then 

 rises to the surface by virtue of the lightness of the liquid contained. 

 This liquid would, of course, be contracted by the cold at the bottom, 

 and the space left would be filled by the sea-water. And the orifice is 

 so arranged, that, when the liquid expands, upon reaching the surface 

 of the water, to its original bulk, the sea-water so entering shall 

 remain and a corresponding portion of the liquid be forced out through 

 the orifice, the volume of the sea- water contained denoting the temper- 

 ature at the bottom. When this is not deemed sufficiently accurate, 

 a tube of mercury, similarly arranged, within an orifice near the bot- 

 tom may be used. A meter, fixed to the machine, denotes the dis- 

 tance through which it has passed, and, by connecting the apparatus 

 for setting free the sinking weight with this meter, the machine may 

 be made to descend to any given depth ; its relative position, when it 

 rises to the surface, determining the force and direction of the cur- 

 rent at that depth. To collect a portion of water at the bottom, or 

 any required depth, a small vessel is attached, upside down, and shuts 

 when in that position by a valve, which, when the disconnecting 

 apparatus sets free the weight and brings the vessel to its proper posi- 

 tion, opens and allows the water to flow in. The thickness of the 

 metal used is -^th of an inch the diameter of the cylinder is 16 

 inches, and the height three feet six inches. "With the disconnecting 

 apparatus it weighs 24 Ibs., and costs about 12. It contains 25 Ibs. 

 of oil of potatoes, and when filled with that liquid, weighs upwards of 

 30 Ibs. lighter than the quantity of water it displaces. To sink it, a 

 couple of cannon-balls, each weighing a quarter of a hundred, would 

 be sufficient. It is obvious that the only loss, each time, is that of the 

 sinking weight, which would give an expense, taking cast-iron at 

 10, of 5s. The time employed in the operation would be less than in 

 the case of the sounding-lead, namely, 4000 fathoms an hour. 



NEW TYPE-COMPOSING AND DISTRIBUTING MACHINE. 



IN the Danish department of the Great Exhibition, was exhibited 

 an ingenious machine for setting and distributing types at the same time 

 the composing part being supplied with types by the distribution of 

 those previously used ; and the distributing part of the machine being 

 placed over the composing part. It rests with its hollow axis on the 

 projected central axis of the latter, and distributes the types by revok- 

 ing on that axis, and conducting each type to that place in the lower 

 part of the machine to which it belongs. Here the types are piled on 

 and between brass rods, of which there are as many as there are letters, 

 characters, or signs wanted for printing. These rods are perpendicu- 

 larly fixed between two plates of metal, in circular order, so that they 

 form an open cylinder. The distributing part of the machine has a 



