Daguerreotype Experiment, 18S 



Art. XV. — A Daguerreotype Experiment hy Galvanic Light ; by B. 

 SiLLiMAN, Jr., A. M., of the departments of Chemistry and Mineral- 

 ogy, in Yale College, and Wm. Henry Goode, 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 in the 

 laboratoi'y of Yale College, consisting of nine hundred pairs of plates, 

 ten inches by four, was charged with 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 charcoal 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 

 rear of 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 

 inadvertently destroyed. The plates used were of inferior quality, 

 being some of the first of American manufacture. 



These experiments were not published at the time they were made, 

 because it was understood, that a gentleman distinguished for his scien- 

 tific investigations, was already engaged in studying this branch of the 

 subject, with whose researches we had no wish to interfere, and the matter 

 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 respecting 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 an alcoholic solution of strontia ; 

 Vol. xLiii, No. 1.— Apiii-June, 1842. 24 



