Daguerreotype Experiment. 185 
Arr. XV.—A Daguerreotype Bepetineht by Galvanic Light ; by B, 
Sruuiman, Jr., A. M., of the departments of Chemistry and Mingte 
ogy, in Yale College, and Wu. Henry Goong, M. D. 
In November, 1840, we succeeded in obtaining a photographic im- 
pression, by galvanic light reflected from the surface of a medallion to 
the iodized surface of a Daguerreotype plate. The large battery i in the 
laboratory of Yale College, consisting of nine hundred pairs of plates, 
ten inches by four, was charged w ith a weak solution of sulphuric 
acid, and its poles adjusted with charcoal points, in the manner which is 
customary, when an intense light is to be produced by means of this 
instrument. Two pictures were obtained ; one of which is made up of 
a blur, or spot, produced by the light from the chareoal points, the 
image of the retort-stand, on which a medallion of white plaster rested, 
and the image of the medallion, but the lines on its face are not given. 
‘The camera was about six feet from the charcoal points, when this 
impression was taken, and the medallion a little on one side, and in the 
rearof the points. The plate was exposed to the light about twenty 
seconds, and no.means were employed either for condensing the light 
on the objects to be copied, or that reflected from them, on the lens 
which gave the image... The only lens employed was a French achro- 
matic, three inches in diameter, : and of about sixteen inches focal length. 
Another picture was taken of the medallion only, which was placed 
about two feet from the charcoal points, and the camera about four feet 
~from. it, and. in such a position that the charcoal points did not come 
within, the: field of, the. lens. . This picture, we regret to say, has been 
d. The plates used were of | are 
being some at the first of American manufacture. ae 
These experiments were not published at Sggnee er Wire made, 
ane it was understood, that a gentleman distir D- 
tific investigations, was already engaged ii studying = branch of the 
subject, w ) 
was abandoned mainly for this reason. “Having! been informed recently, 
however, that this gentleman had also abandoned. it, we have concluded 
to give this account of our experiments. ; 
- On the same occasion, an observation was made Seapectitt the image 
given by the two charcoal points, when they were nearly in contact, 
and the battery in full operation, which we do not remember to have 
met with elsewhere. An image of each charcoal point is given, 
separate from that of the other, by a lens placed at a little distance. 
These two images differ remarkably in color; one is of the color of the 
flame afforded by the combustion of — solution of strontia; 
by 
Vol. xtin, No. 1.—April-June, 1842. 
