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  The research archive of Gary W. Ewer regarding the history of the daguerreotype

Two items for today: one brief anecdote, and a longer technical item... On this day (June 27) in the year 1840, the following notice appeared in "Niles National Register": - - - - - - - - - - - - - - - - - Daguerreotype--A gentleman who sat half a minute to have his miniature taken by the Daguerreotype, was surprised, on looking at the picture, to see a spot on his cheek which he was sure did not belong to him. Daguerre would have been set down a liar at once, but for his well established reputation of always speaking the truth; yet there was a plain contradiction between the picture and the original, as they both stood together. A microscope was brought, and then the spot was seen to be the well-defined miniature of a fly, who had seized that occasion to get his own likeness taken, and so had stood upon the gentleman's cheek unobserved. [N.Y. Jour.Com.] * * * * * * * * * From "The American Journal of Science and Arts" (New Haven; Vol. XLIII, No. 1.--April-June, 1842): ART. XV.-- A Daguerreotype Experiment by Galvanic Light; by B. SILLIMAN, Jr., A. M., of the departments of Chemistry and Mineralogy, in Yale College, and WM. HENRY GOODE, M.D. In November, 1840, we succeeded in obtaining a photographic impression, by galvanic light reflected from the surface of a medallion to the iodized surface of a Daguerreotype plate. The large battery in the laboratory 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 achromatic, 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 scientific 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; the other resembles in color, the flame produced by the combustion of an alcoholic solution of chloride of sodium, more nearly than thing else with which we can compare it. The charcoal points were shifted, each to the opposite pole of the battery, without producing any change in the color of the light given off by the poles respectively. Other pieces of charcoal were substituted, in the place of those with which this phenomenon was first observed, but the difference in the color of the two images was always present, and did not seem to be connected in any manner with the particular charcoal points employed, but the yellow image was uniformly given by one pole, and the purple image by the other pole of the battery. We are under the impression, that the yellow colored image was produced from the charcoal point, in connection with the positive pole of the battery, and that the strontia colored image came from the negative pole of the battery, though of this no note was made at the time. No attempt was made to ascertain by direct experiments, whether these images possessed. a different degree of power or not, in producing an impression upon an iodized plate. The difference in their color was presumptive evidence that one image, (that from the negative pole,) possessed more of the chemical rays than the other. But evidence is (we are of opinion) afforded indirectly that such is the fact. The light from both charcoal points made a slight impression on the iodized plate, before they were brought so close together as to unite in forming a general blur: these two small spots or impressions are nearly opposite or at each extremity of one diameter of the blur, and without its circumference; one of them is more distinct than the other. Within the edge of the blur, and nearly in the same diameter with the two spots above named, there are also two impressions, darker and more strongly marked, than is the general impression made by the light from the points. One of these spots is doubtless made by the light from one point, while the other is due to the light from the other point, and one of them far exceeds the other in distinctness. Now the more strongly marked spot without the blur, and the more strongly marked one in it, are close to each other on the same edge of the blur, and are doubtless produced by the light from one and the same charcoal point. The two other spots, viz. that without, and that within the blur, which are much less distinct, are close to each other at the opposite extremity of the diameter of the blur, and are also evidently produced by the light from the other charcoal point. Yale College Laboratory, June 20, 1842. ----------------------------------------------------------------- 06-27-96

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