M. TECHNOLOGY. 533 



of magnesium is formed anew. By the reaction of the hydro- 

 chloric acid upon this compound, chlorine and the double chlo- 

 rides are reproduced, and these double chlorides may again 

 be shut up, and thus the process rendered continuous a defi- 

 nite quantity of manganese and magnesium being able to 

 eliminate an indefinite amount of chlorine from hydrochloric 

 acid. 15 A, August 24, 1872, 238. 



ZUCCATOR COPYING- MACHINE. 



The electro-chemical copying-press devised by Signor Eu- 

 genio de Zuccator, of Padua, has been materially improved 

 since its first announcement, and now bids fair to realize meas- 

 urably the object of a simple and ready method of multiply- 

 ing any writing, printing, or drawing, by electro-chemical ac- 

 tion, for the use of editors, telegraphers, reporters, etc. The 

 copying-press itself differs but little from the screw-press in 

 ordinary use, the difference being mainly in having the upper 

 bed composed of a plate of copper, and the lower of a plate 

 of copper tinned, both on mahogany beds, the upper being at- 

 tached to the solid iron press by clips, and the lower being 

 made to slide out. These two plates are placed in the ordina- 

 ry way in the circuit of a battery, so that when brought into 

 close proximity by the action of a screw the circuit is com- 

 pleted, and the current established over the whole surfaces. 



A steel plate is coated with an insulating varnish, and upon 

 this the writing or drawing is traced. When this plate is in- 

 terposed in the circuit, the current of electricity is confined 

 to those portions deprived of the insulating surface, and leaves 

 a record of its passage by its continued action on the steel 

 plate and on sheets of copying-paper, especially prepared and 

 dampened with a solution of prussiate of potash. The elec- 

 trolytic action causes the formation of the ferro-prussiate, or 

 "Prussian blue," producing a perfect fac-simile of the origi- 

 nal manuscript or design upon the varnished surface of the 

 plate. 



The movable steel plates on which the writing or drawing 

 to be copied is made must be thoroughly cleaned, and well 

 and evenly varnished, care also being taken, by a firm and 

 steady pressure on the style, to remove the varnish, leaving 

 the writing, printing, or other pattern, in bright steel on a 

 raised ground of varnish, affording perfect insulation every 



