The Daguerreian Society

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":
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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.
Posted for your enjoyment.      Gary W. Ewer       

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