376 Scientific Inielligence.— Chemistry. 
rent developed in the experiment doubtless then co-operates, but 
probably in a different manner from what the author seems to msinu- 
ate: Is-it not evident that there is a relation between the ascent of 
the mereury along the wires, and the singular motions which an elee- 
tric current, however feeble, imprints on this metal? We may be 
easily satisfied of the reality of this connection, by consulting the 
works of Erman, Serullas, Herschel, and especially the phenomena 
recently described by M. Nobili, which appear to have a more im- 
— emery to the facts above stated.— Bib. Univ. Juin, 1829. 
6. Colored Steel Plates—M. Nobili, in passing through Geneva 
some time since, shewed to several persons some steel plates, on 
which he had» sueceeded in impressing perfectly regular figures, 
which presented all the colors of the rainbow, blending: with. each 
other, and shaded in a thousand different modes. The inventor has 
not made known: the details of his process. He had. previously 
shewn, that if one of the poles of a battery is made to communicate 
with-a very smooth metallic plate ; and the other with a platina wire; 
ending in’ a point, and: placed in a direction perpendicular to the 
plate and very near it, (about half a line) a portion of the elements 
of the liquid, interposed between the point of the wire and the plate, 
deposits an extremely thin stratum on the latter, which determines @ 
suecession of colored rings. ‘The number, size, and nature ‘of these 
rings, exactly similar in their appearance and origin, to those which — 
are produced by thin plates, appear to depend on many circumstan~ 
ces,—among which are the nature of the plate on which the deposits 
are made, and'that of the decomposed fluid. But what the fluids are 
which M.-Nobili employs to color his steel plates, how he disposes 
his-apparatus to produce this variety of forms and shades, is what he 
has not made manifest :—it is a secret which must be held in respect; 
and which we: shall i to ee eee 
— ae —Idem. a 
as “Chemical action of light —The following: noni are é ened by Me 
Fischer, as proper to be added to those which demonstrate the 
ehemical action of light upon organic matter. If a solution of ferro- 
‘Prussiate of potash be precipitated by alcohol, and the precipitate be 
quickly collected and dissolved in water, the solution, exposed to 
poet pass rapidly from yellow to green, and at length prussian 
Ik be deposited. The solution becomes at the same time al- 
