124 DIVINO BELL. 



purpose of enlarging it and making it truly cylindrical. The sheaves are 

 then finished by the face-turning lathe, which has a sliding rest that 

 supports the turning tool, and moves it slowly across the face of the 

 sheave. As the face of the -sheave which is thus turned is composed 

 partly of the metal coak and partly of wood, and as it has been found by 

 experience that different velocities are required for turning wood and 

 metal, the machine has a very ingenious contrivance for changing the 

 velocity when the tool passes from the wood to the metal. 



Besides the machines already mentioned, there are five others, (viz.) 

 the turning lathe, by which the iron pins are cut to their proper diameter; 

 the polishing engine, by which they are polished, and which is sure to 

 detect those that have flaws in them : the machine for boring very large 

 holes in any position, which is used for the largest size of blocks ; the 

 machine for making dead-eyes, and the other for making tree-nails, used 

 in fastening the planks to the timbers of ships. 



By this machinery the blocks are made with the nicest precision ; a 

 quality which was always found wanting in those made by hand, which 

 oftentimes rendered them unserviceable at the moment when the 

 quickness of their movement was intimately connected with the fate of 

 the ship. 



To give a pretty accurate idea of the expedition of these beautiful 

 works, we will state the number of blocks that can be made per day. 

 The first set of machines make those from four to seven inches in length 

 at the rate of 700 per day; these have wooden pins. The second set 

 make those from eight to ten inches in length at the rate of 520 per 

 day; these have iron pins. The third set make those from eleven to 

 eighteen inches in length at the rate of 200 per day; so that upwards of 

 1,400 blocks may be made daily! All the blocks for the service of the 

 Navy are supplied from these machines. 



THE DIVING BELL. 



The first diving bell which we read of in Europe was tried at Cadiz, 

 by two Greeks, in the presence of C'harles the Fifth, and many thousand 

 spectators ; it resembleli a large kettle inverted. The first introduced into 

 this country was in the reign of Charles the Second, by one Phipps, an 

 American black-smith, and who, from the fortune which he acquired by 

 going down to a rich Spanish Galleon, laid the honours of the Mulgrave 

 family, the head of which is no'v the Marquis of Normandy. 



