MECHANICS AND USEFUL ARTS. 59 



of the latter is a large drum, with a projecting eccentric flange, or 

 rail, fastened to its periphery. The head of the piston, which moves 

 the blocks, grasps this rail, but is guided in a straight line by a guide- 

 rest, so that when the drum revolves, the piston-rod will be guided 

 backwards and forwards by the angular part of the rail, but it will be 

 stationary while that part of the rail around the end of the drum is 

 passing through the jaws of the piston-head. This gives the piston- 

 rod and blocks attached an intermittent reciprocating motion. The 

 printing-blocks are secured to the plattens on the inside, but the latter 

 are placed a little distance below the paper, and are secured to coiled 

 springs at the corners, which allow the blocks to be pressed down, 

 but raise them up when the pressure is removed. The plattens, 

 therefore, have square stationary frames around them, all connected 

 together, and slide along on the table guided by up-raised rails on 

 each side, which tit into grooves in the platten-frames. From the 

 framing above, three spring pistons are suspended, which are forced 

 down on the plattens to make the impressions during the inter- 

 missions of the blocks. There are, therefore, four cams on the shaft 

 above, the middle ones being double and the other two single. The 

 side cams alternately press down one block on to color cushions to 

 supply it with color, and the middle ones press down the block which 

 makes the impression, so that the motion of the cams coincides with 

 that of the piston-rods. Thus much for the operating of the blocks. 

 The paper is fed under the blocks on the cross-table, between guide- 

 plates. The paper passes through to a small catching-bar, which has 

 a vibratory motion, and catches and lets go, to draw the printed paper 

 from under the blocks, and to feed in unprinted paper for the next 

 impression. The catching-bar is operated by crooked levers, secured 

 to one of the block frames, and oscillating on a pivot fixed on a block 

 of the feed-table. All the motions are thus in harmony with that 

 of the drum which works the whole. For certain kinds of work 

 the advantages of this machine are apparent. Scientific American. 



MANUFACTURE AND USE OF COPPER TYPE. 



A MACHINE has been invented and patented in England, for the 

 manufacture of printing-fypes, without fusing the metal and pouring 

 it into moulds. The inventor, Mr. Petit, effects his process by the 

 use of steel dies and matrices, w 7 hich, by means of powerful pres- 

 sure, impress the letters and characters on copper, fashioned into 

 quadrangular strips of an indefinite length, wound round a cylinder ; 

 the type being struck, or punched, the same moment that its size is 

 mathematically determined. The machine exhibited to the Royal 

 Society, in June last, produced 32 types per minute ; but by the ap- 

 plication of a small steam-engine to the type-making machinery, it is 

 estimated that 60 per minute can be struck, or 36,000 per diem. The 

 types thus produced possess the utmost sharpness of outline and 

 hardness, in consequence of the superiority of the metal employed 

 and the pressure to which they have been subjected. The hardness 



