M. TECHNOLOGY. 513 



M. TECHNOLOGY. 



XEROGRAPHY, A MANIFOLD WRITING AND PRINTING PROCESS. 



By the following process, devised by Hansen, it is said 

 that about 100, or even 200, copies of a manuscript may be 

 taken in ten minutes. In manipulation it is similar to that 

 with oiled paper saturated with a pigment, except that in this 

 case the colored paper is placed beneath, with the colored 

 side uppermost, and upon it, instead of writing-paper, a sheet 

 of firm, thin, very dry oiled paper is laid that will take up 

 the color without absorbing it. There may be a pile of five, 

 or even ten, such layers of alternate colored and oiled paper, 

 and when it is written upon with a pencil or stylus, a copy in 

 reverse will be formed on the lower side of each leaf of oiled 

 paper. From each of these about twenty impressions can be 

 taken by placing writing-paper in contact with each one, and 

 subjecting the w r hole to the pressure of a rolling -machine, 

 then removing the impressions, renewing the writing-paper, 

 and subjecting the whole to somewhat greater pressure than 

 at first; repeating the operation with increased pressure for 

 each impression up to the twentieth. It is only the blue pa- 

 per that will afford so many impressions, and it must be thin, 

 and the color must be much more finely ground than it is 

 usually found in the trade. The paper on which the impres- 

 sions are taken must not be rough, nor should it be too 

 smooth, and the first impressions should be made with the 

 least possible pressure. The printing, copying, or even the 

 lithographic press is not well adapted to this w T ork. If only 

 twenty copies are desired, an ordinary pen in writing will an- 

 swer. 8 C, September 17, 1874, 332. 



STAMPING - INK. 



An excellent stamping -ink that dries rapidly and is free 

 from grease may be cheaply prepared, according to Miiller, 

 by dissolving one part of crystallized so-called red aniline 

 violet in 30 parts of alcohol, and adding 30 parts of glyce- 

 rine to the solution. This colored liquid is poured upon the 

 cushion and rubbed with a brush. 5 <7,XXXVIIL, 1874, 271. 



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