376 Scientific Intelligence. — Chemistry. 



rent developed in the experiment doubtless then co-operates, but 

 probably in a different manner from what the author seems to insinu- 

 ate. Is it not evident that there is a relation between the ascent of 

 the mercury along the wires, and the singular motions which an elec- 

 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, SeruUas, Herschel, and especially the phenomena 

 recently described by M. Nobili, which appear to have a more im- 

 mediate relation 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 succeeded 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 a 

 succession 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. NobiU 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 endeavor not to pry into until its author shall 

 have made it public. — Idem. 



1. Chemical action of light. — The following facts are cited by M. 

 Fischer, as proper to be added to those which demonstrate the 

 chemical 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 

 light, will pass rapidly from yellow to green, and at length prussian 

 blue vnll be deposited. The solution becomes at the same time al- 



