52 H.J. Grayson : 



adjustment and lock nut for regulating its height. The top surface 

 of the pillar is hardened and polished, and serves as an arrest for a 

 hardened spherical projection extending from the main lever imme- 

 diately under the pawls. The arresting pillar and its adjustments 

 are attached to a separate base plate (11) extending out from the 

 base of the main l>ed of the machine to which it is bolted. The 

 two screws, the heads of which are shown on 11, have no relation 

 to Bj tliey, however, prevent any flexure of 11, due to the weight 

 of the lever and counterpoise (65) descending upon it. It is, of 

 course, important that all movements affecting the ruling be regu- 

 lated to avoid the sudden arrest of any movement affecting the 

 operation of the diamond point ; hence the provision throughout the 

 machine of a variety of parts necessary to its protection. Reference 

 to Plates VII., VIII. and X. wdll serve to supplement the brief 

 description of the features indicated. 



Passing to base plate C. A glance at the plan will show that it is 

 complementary to B in its relation to D and the main bed of the 

 machine, to both of which it is similarly attached. Plate VII. shows 

 its position, and indicates in perspective its purpose. It forms the 

 base of a rigid pillar, of cast iron, supporting a frame which 

 carries the two steel rods (50). These rods, both of which are 

 accurately ground, mainly serve as guides to a small platform of 

 steel, through the agency of which the ,eccentric swing or throw of 

 the crank rod (52) is converted into a steady, even horizontal " to 

 and fro " motion, as free as possible from any kind of constraint. 

 This movement can be communicated to the ruling carriage as 

 required. The transmission of a smooth and even motion is due 

 primarily to the attachment of the connecting rod (52) to 

 a rotating crosshead placed between the two guides (50) im- 

 mediately below tlie lower plate or base of 49 ; and in 

 part to the carefully fitted sleeves sliding on 50. To the 

 upper surface of platform 48, are secured the various adjust- 

 ments needed to effect and control the motions of the ruling car- 

 riage, the chief of these being the centre block (47), which is rigidly 

 screwed to the surface of 48. The communication rod (44) passes 

 through the centre of 47, one end screwing into a rocking bar on 

 the ruling carriage, the other resting partly in a guide frame (45) 

 and partly in block 47. On opposite sides of the latter (47) are 

 small sleeves or clamps fitted with binding screws; these, if free or 

 clamped at a sufficient distance from 47, will permit 44, on which 

 they travel, to slide freely through 47 without communicating any 



