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, See Electrography. | _ 157 
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Arr. XIX.—Electrography or the Ellectrotype.* 
Instructions for the Multiplication of Works of Art in Metal 
by Voltaic Electricity ; by Tuomas Srencer. (Part IV of 
- Griffin’s Scientific Miscellany: Glasgow, 1840, pp. 62.) 
Ir is now about three years since we were first informed in the ~ 
public prints, that Prof. Jacobi, of St. Petersburg, had succeeded 
in producing lines of metallic Se in relief, upon plates of the 
same metal, by pape: von’ solutions of the ec es of 
that metal, ey aid of Voltaic electricity. 
Since that time very many experiments have been ineciecte: 
on the subject, all having the same object in view, viz. the pro- 
duction of perfect metallic casts or copies of medals, copper-plates, 
and other works of art. But no one has attained the object more 
perfectly or by more simple means than Mr. S pencer, of Liverpool, 
Whose attention was called ‘to this subject before any thing was 
known by him of what Prof. Jacobi had done. We do not pre- 
tend to give an opinion as to the priority of claim which either 
of these gentlemen may have to the process in question, since we 
deem it quite possible each may have pursued his own re- 
searches, both leading to me result, without any knowledge 
of what was doing by the other; and without the slightest inten- 
tion of interference. 
The conditions necessary to the success of this process are the 
following. 1. Two fluids, one of which must be a saturated so- 
lution of the salt, on the negative side of a Voltaic series ; the oth- 
€r may be, either water slightly acidulated with salphuric acid, 
or a weak saline solution, as sulphate of soda. 
2. These two fluids must be in contact without mixture; this 
is effected by placing them in a vessel provided with a porous di- 
Vision, such as plaster. of Paris, unglazed earthen ware, brown 
paper, bladder, ealf-skin, or other animal membrane. 
ee 
re 
bows it eihichisag ade many months since on this rest Lew and ‘nati others. 
Our chives will be found in the above notice of Mr. Spencer’s pamphiet. 
Ina Liv aper, we find an ardent vindication of Mr. Spencer's claim to 
Priority and pinion axcelionce i in the results. 
