656 



PRINTING MACHINE 



from one cylinder, to travel round the peripheries of the cylinders and drums, at such 

 a rate as to meet the types of the second side at the exact point which will ensure 

 this side falling with geometrical nicety upon the back of the first. For this purpose, 

 the cylinders and drums must revolve at the very same speed as the carriage under- 

 neath ; hence the least incorrectness in the workmanship will produce such defective 

 typography as will not be endured in book-printing at the present day, though it may 

 be tolerated in newspapers. An equable distribution of the ink is of no less import- 

 ance to beautiful letter-press. See Jiffs. 1683, 1684. 



1683 - 1684 



Applegath and Cowper's single. 



Applegath and Cowper's double. 



The machines represented in figs. 1685, 1686, 1687, are different forms of those 

 which have been patented by Messrs. Applegath and Cowper. That shown in figs. 

 1685, 1687, prints both sides of the sheet during its passage, and is capable of throw- 

 ing off nearly 1,000 finished sheets per hour. The moistened quires of blank paper 

 being piled upon a table, A, the boy, who stands on the adjoining platform, takes up 

 one sheet after another, and lays them upon a feeder B, which has several linen 

 girths passing across its surface, and round a pulley at each end of the feeder ; so 

 that whenever the pulleys begin to revolve, the motion of the girths carries forward 

 the sheet, and delivers it over the entering roller E, where it is embraced between two 



1685 



series of endless tapes, that pass round a series of tension rollers. These tapes are so 

 placed as to fall partly between, and partly exterior to, the pages of the printing; 

 whereby they remain in close contact with the sheet of paper on both of its sides during 

 its progress through the machine. The paper is thus conducted from the first printing- 

 cylinder F, to the second cylinder o, without having the truth of its register impaired, 

 so that the coincidence of the two pages is perfect. These two great cylinders, or 

 drums, are made of cast iron, turned perfectly true upon a self-acting lathe ; they are 

 clothed in these parts, corresponding to the typographic impression, with fine woollen 

 cloth, called blankets by the pressmen, and revolve upon powerful shafts, which rest 

 in brass bearings of the strong framing of the machine. These bearings, or plummer 

 blocks, are susceptible of any degree of adjustment, by set screws. The drums, H 

 and i, are made of wood ; they serve to conduct the sheet evenly from the one printing- 

 cylinder to the other. 



One series of tapes commences at the upper part of the entering drum E, proceeds 

 in contact with the right-hand side and under surface of the printing-cylinder r, 

 passes next over the carrier-drum H, and under the carrier-drum i; then en- 

 compassing the left-hand side and under portion of the printing-drum o, it passes 

 in contact with the small tension rollers a, b, c, d,fig. 1687, and finally arrives at the 



