518 ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



grains in this way furnish the finest tones, while the halftones 

 are supplied by those of medium size. This paper can be 

 prepared like carbon paper, without chrome salt, and ren- 

 dered sensitive before use. 18 (7, March 6, 1872, 154. 



NEW PHOTO-LITHOGRAPHIC PROCESS. 



According to the London JVews, a new system of photo- 

 graphic lithography has been introduced in Berlin, based upon 

 the fact that caoutchouc, like Jew's pitch and some other hy- 

 drocarbons, is capable of receiving a photographic impres- 

 sion. A thin film of caoutchouc dissolved in benzole is first 

 spread upon paper, and exposed in the camera in the usual 

 manner. The portions which have been subjected to the ac- 

 tion of light are rendered insoluble, and the other portions 

 are then washed away, as in Mr. Pouncey's process. The 

 caoutchouc, wherever it remains on the paper, will receive a 

 greasy ink from a roller which is now passed over the sheet, 

 and the impression thus obtained may be transferred to the 

 lithographic stone, and printed from in the usual manner. 

 The plan is virtually a reproduction of Pouncey's process, 

 with the substitution of caoutchouc for the bitumen of Judasa. 

 22 A, March 9, 1872, 247. 



MODE OF REPRODUCING MANUSCRIPT. 



An ingenious application of science to commercial purposes 

 has been made by an Italian gentleman, M. Eugenio de Zuc- 

 cato, of Padua. By means of the invention, any number of 

 copies of a manuscript or design, traced upon a varnished 

 metal plate, may be produced in an ordinary copying-press. 

 The modus operandi is very simple. To the bed and upper 

 plate of a press are attached wires leading from a small bat- 

 tery, so that when the top of the instrument is screwed down 

 the two metal surfaces come into contact, and an electric cur- 

 rent passes. An iron plate resting upon the bed of the press 

 is coated with varnish, and upon this surface is written with 

 a steel point any communication it is desired to copy. The 

 letters having thus been formed in bare metal, a few sheets 

 of copying-paper are impregnated with an acid solution of 

 prussiate of potash and placed upon the scratched plate, 

 which is then subjected to pressure in the copying -press. 

 An electric current passes wherever the metal has been left 



