186 Mr. Cowper on the 



In these machines the type was made to pass under the cylinder, 

 on which was wrapped the sheet of paper, the paper being firmly 

 held to the cylinder by means of tapes ; the ink was placed in a 

 cylindrical box, from which it was forced by means of a powerful 

 screw depressing a tightly-fitted piston ; thence it fell between two 

 iron rollers; below these were placed a number of other rollers, two 

 of which had, in addition to their rotatory motion, an end motion, 

 i. e. a motion in the direction of their length ; the whole system of 

 rollers terminated in two which applied the ink to the types. 

 (Fig. 4.) 



In order to obtain a great number of impressions from the same 

 form, a paper cylinder (i. e. the cylinder on which the paper is 

 wrapped) was placed on each side the inking apparatus, the form 

 passing under both. This machine produced 1100 impressions per 

 hour; subsequent improvements raised them to 1800 per hour. 



The next step was the invention of a machine, (also by Mr. 

 Koenig,) for printing both sides of the sheet. It resembled two 

 single machines placed with their cylinders towards each other, at 

 a distance of two or three feet, — the sheet was conveyed from 

 one paper cylinder to the other by means of tapes — the track 

 of the sheet exactly resembled the letter S, if laid horizontally, 

 thus, CZ2 : in the course of this track the sheet was turned over. At 

 the first paper cylinder it received the impression from the first 

 form, and at the second paper cylinder it received the impression 

 from the second form — the machine printed 750 sheets on both 

 sides per hour. This machine was erected for Mr. T. Bensley^ 

 and was the only one Mr. Koenig made for printing on both sides 

 the sheet — this was in 1815. (Fig. 5.) 



About this time Messrs. Donkin and Bacon were also contriving 

 a printing machine ; having, in 1813, obtained a patent for a 

 machine in which the types were placed on a revolving prism — 

 the ink was applied by a roller which rose and fell with the 

 irregularities of the prism, and the sheet was wrapped on another 

 prism, so formed as to meet the irregularities of the type prism : 

 one of these machines was erected for the University of Cambridge, 

 and was a beautiful specimen of ingenuity and workmanship ; it 

 was, however, too complicated, and the inking was defective, which 

 prevented its success. Nevertheless a great point was attained ; 

 for in this machine were first introduced inking rollers covered with 

 a composition of treacle and glue ; in Koenig's machine the rollers 

 were covered with leather, which never answered the purpose well. 

 (Fig. 3.) 



