COPIES OF WRITTEN PAPER BY PRESSURE. ] JQ 



copy, this invention has been of so great utility, that it has 

 now come into very general use. 



The method of using this instrument, which is a rolling Method of 

 press, is briefly this : Having covered the paper to be copied usin S ■*■ 

 with a piece of damp copying paper (a kind of white, thin, 

 unsized paper, made on purpose), place it between oiled pa- 

 pers on a board, cover it with some blotting paper, and pass 

 it through the press: a copy, which is legible through the 

 copying paper, is thus obtained from writing that has been 

 written only a few hours. Thus far this machine fully an- 

 swers the purpose ; but when old writing is made to undergo Does not an- 



this process, no effect is produced. swerforold 



writing. 

 Should any method be discovered of obtaining copies from 



old writing, it would prove a valuable acquisition to many 

 persons, and to me in particular. It Js with the view of obtain- 

 ing information on this subject, that 1 have troubled you with 

 this letter; you, or some of your correspondents will, 1 hope, information©* 

 through the medium of your valuable Journal, favour the this head de- 

 public with some communication, that may throw a light on 

 this interesting subject. 



The following account of a few experiments I have made 

 will, perhaps, be of service in forming a judgment as to the 

 means most likely to succeed ; or they may be useful to any 

 one, who may choose to prosecute the matter experimentally. 



I remain, Sir, 

 Your obedient servant, 

 To Mr. NICHOLSON. R. T. 



f first tried the most violent pressure (both with and with- Experiments. 

 out the substances hereafter mentioned), without advantage. 

 A moderate pressure is best. Writing can seldom be got out ° JJJbest. 

 after it has been written more than 24 hours. 



In taking off writing, a considerable improvement was dis- 

 covered ; it consists in covering the copying paper with flannel 

 instead of oiled paper. By glueing the copying paper on. a 

 piece of white paper, the writing is rendered more legible. 

 Notwithstanding these, and using boiling water instead of 

 cold, the old writing continued refractory. 



Mechanical 



