iiil4 On Printing Presses and their Theory. 



are fifteen inches each in length ; and in the position repre- 

 sented in the figure, which is that of the greatest obHquity^ 

 they want two and a quarter inches at their point of contact 

 of being straight. The lower end of each lever is four inch- 

 es broad, and is rounded off into a portion of a cylindrical 

 surface of half an inch radius. A piece of steel fixed within 

 the circular projection in the middle of the platen has a hol- 

 low bush or bed of corresponding figure : in this the lower 

 end of the lever (17) is set. The upper end of this lever is 

 hollowed out in the same manner to receive the lower end 

 of (6) ; and the upper end of (6) to receive a projection 

 from the under side of the top of the frame. At (5) there 

 is a provision for raising or lowering this projection by slips 

 of sheet iron or tin, and thus adjusting the position of the 

 levers to the best working state. The ends of the levers 

 and the beds in which they rest are overlaid with steel, and 

 the beds are so contrived as permanently to retain a small 

 quantity of oil. (9) is a spindle of wrought iron fastened at 

 the upper end by a screw and nut to the shorter arm of the bal- 

 ance lever (7), and branching below into three parts, each of 

 which is attached by an adjusting screw to the platen. This 

 answers the double purpose of keeping the platen steady, 

 and enabling the weight (18) attached to the longer arm of 

 the lever (7) to lift the platen and carry back the bar imme- 

 diately after each pull. The platen is still farther guided 

 by lateral projections which run in grooves connected with 

 the cheeks of the press. 



The mode in which the movement of the working bar 

 (12) is transmitted to the main levers, will be best under- 

 stood from Fig. II. which is a representation of the parts 11, 

 12, 13 and 15, as they would appear to an eye looking down 

 upon the press from above. The bar BA (the lever work- 

 ed with the hand) is inserted into a strong cast iron roller 

 (13), which turns in sockets secured to the right cheek of 

 the press. From this roller, about six inches above the bar, 

 proceeds an arm AC three inches in length, and to the ex- 

 tremity of this is connected by a joint the driving lever CD, 

 twenty-one and a half inches long. The extremity D is 

 connected in a similar way with the iron rod EF, one end 

 of which slides in a pewter guide (represented by 10, in 

 Fig. I.) while the other end is fastened by a hook and eye 

 to the upper main lever (6), at the distance of an inch froro 



