Chemistry. 113 
successfully transferred by pressure the splendid tints of the pearl 
to black wax, fusible metal, balsam of tolu, lead, tin, and various other 
substances. ‘The colors displayed by fusible metal possess at first 
extraordinary beauty, which in a short time is partially lost, owing to 
a change that occurs upon the surface of the metal. 
A few months ago, while engaged upon some experiments in elec- 
trotyping, I was led to think that by this process the hues of the pearl 
might be readily transferred to those metals, which from their hardness 
are incapable of receiving impressions in mass, but yet, on account of 
their freedom from oxidation, retain for a long time a surface compara- 
tively pure. I therefore took a Smee’s battery, which I had just con- 
structed, and after several experiments succeeded in obtaining small 
sheets of silver, radiant with the hues of the shell. When seen by a 
single light, as that of a lamp, the play of colors is surpassingly beau- 
tiful, scarcely inferior to that of the pearl; and where equal care was 
employed, the plate of silver, which was formed eight months ago, 
rivals in brilliancy that which came fresh from the battery a few hours 
since. 
The process by which this result is obtained is as follows. ‘The first 
thing required is to prepare the shell. This is effected by grinding, 
and polishing it upon the back, in such a manner as to cut through the 
numerous concentric strata that compose its substance. When this is 
done, by the aid of a microscope the surface will be seen covered with 
delicate grooves, some thousand in an inch, formed by the sections of 
the concentric laminz, and this configuration gives rise to the glowing 
tints of the shell. The next step is to obtain an exact impression of 
this surface upon some good conductor of electricity. ‘This we are 
enabled to do by means of fusible metal, if proper precautions are 
employed in taking the impression. I pursue exactly the same method 
as in taking the copy of amedal. After fusing the metal, I pour it upon 
oiled paper, and when the air bubbles cease to rise through the metal 
the oxide is skimmed from its surface with a card, and as soon as it 
presents the appearance of a perfect mirror the shell is forced down 
upon it by a sudden pressure. When the metal has cooled | remove it 
from the shell, and having ascertained the accuracy of the impression, 
immediately plunge it, before any change of the surface can occur, into 
the silver solution, thereby completing the circuit between the poles of 
the battery. In a few moments the surface of the metal is frosted with 
silver, and the configuration of the shell exactly copied. A sheet of 
silver, of sufficient thickness to be easily removed with a pen-knife, 
will be deposited in the course of five or six hours under favorable cir- a 
cumstances. The battery I have employed consists of two plates of 
amalgamated zinc and one of platinized silver, six inches by eight. . 
Seconp Series, Vol. I, No. 1.—Jan. 1846 15 
