94 
ARTICLE Y. 
Memoir on Colours in general, and particularly on a new Chro- 
matic Scale deduced from Metallochromy for Scientific and 
Practical Purposes. By M. Leopotp Nosiut of Reggio. 
From the Bibliotheque Universelle des Sciences, §c. vol. xliv. xlv. Geneva. 
(1830, vol. 1. p. 337, vol. m1. p. 35, Aug. and Sept.) 
iT DISCOVERED in 1826 a new class of facts and gave them the name 
of electro-chemical appearances. The following is one of the principal 
experiments connected with those facts. 
A plate of platina is laid horizontally at the bottom of a vessel made 
of glass or china. A platina point is vertically suspended over this in 
such a manner that the distance between the point and the plate may be 
about half a line. A solution of acetate of lead is next poured into the 
vessel so as not only to cover the plate, but to rise two or three lines 
higher than the point. The plate and the point are now brought into 
communication, the former with the positive and the latter with the ne- 
gative pole of an electric pile. At the moment when the voltaic circuit 
is closed, a series of rings similar to those formed at the centre of the 
Newtonian lenses is to be seen on the surface of the plate precisely under 
the point. This fact, which could not fail to strike any one observing 
it for the first time, led me to the discovery of others, which I have com- 
municated to the public in four successive Memoirs*. I foresaw from 
the very first the advantages that the arts were likely to derive from 
this new method of colouring metals; but it was not until toward the 
close of 1827 that I began to attend seriously to its application. My 
first attempts I forbear to mention, being more desirous to call attention 
to the productions which I obtained in the course of 1828, and in the 
November of that year presented to the French Institute. These pro- 
ductions consisted of several plates of coloured metal, and excited the 
particular attention of that illustrious body by the beauty and vividness 
of their tints, the precision of their outlines, and the softness of their 
blendings+. . 
* Bibhioth. Univ. vol. xxxut. xxxiv, xxxv. xxxvi. (Old Series.) Annales de 
Chimie et de Physique, vol. xxxiv. and xxxv. 
+ [A specimen of the productions of this beautiful art was presented by the 
inventor to the Royal Society, in whose Library it may be seen —En1r. ] 
