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John A. Whipple, "Microscopic Daguerreotypes"
Photographic Art-Journal, October 1852

Friend Snelling.—Seeing, in your September number, an article with the above heading, reminded me of my promise to write for your most excellent Journal my experiments in that department of the photographic art. In 1846, it was suggested to me by Rev. S. Adams, of this city, that it might be possible to daguerreotype the image of the microscope; he was in possession of a fine "Oberhouser," which he loaned me for the trial. By removing the lense from the camera, and substituting the microscope in its place, and adjusting the object properly for seeing with the naked eye, a clear but very faint image was found projected upon the ground glass; the light being so weak that it was hardly possible to focus it. But doing that as well as I could, and submitting a plate to its action, giving an exposure of one and a half hours, then mercurializing; great was my astonishment and delight, when upon lifting the plate to take a peep, I saw a clear and distinct image there, thus demonstrating the possibility of indelibly fixing those hidden forms of nature now beheld by our unaided vision. The object tried was the mandible of a small spider, so small that it could only be discerned as a mere speck by the naked eye; it was magnified on the plate to cover three-fourths of an inch surface, and every part was rendered in bold relief, showing its little comb-like appurtenances to perfection, equally as well as represented to the eye in the instrument, the only defect in this first proof was a small light spot exactly in the middle of the plate, which we found was caused by a prism used in the microscope to reflect the image at right angles. On removing that, the next proof was without a blemish. My next experiment was with test object scales of the Sepizma; and truly they were a test for daguerreotyping. I could do every part well enough but the cross striae, which are only brought out with instruments of the very best manufacture; when so high a power is used as is here necessary, a great loss of light is experienced, requiring an exposure of many hours, which every one acquainted with daguerreotyping, knows is not favorable to fine results. I succeeded in doing them with the finest instrument, as well as a second-rate one would show them to the eye. I find a much better way for ordinary purposes, instead of a microscope with eye-pieces, is to use simply a double or treble achromatic, of a combined focus, of from one-fourth to one inch in length, according to the character of the object and the extent desirable to magnify; a section of woody fibre, for instance, an eighth of an inch in diameter, an image of which it would be desirable to impress on a plate five inches in diameter, (seen as a transparent object), I should use a lense about half-an-inch focus, and all that is to be done to do it is to have these little lenses set in the brass plate which will screw into the camera where the daguerreotype lens unscrews, then support the slip of wood to be magnified half-an-inch before the lense, on a little slide prepared to hold it, that can be made to move back and forwards a quarter of an inch or so, then by pointing the camera towards the rim, and having the wood just in the focus of the small lense, a beautiful distinct magnified image of it will be seen on the ground glass of the camera, in size just in proportion as the camera box is lengthened or shortened, and the wood supported on the stand moved nearer to or further from the lense. If the box is lengthened and the object moved slightly towards the lense, the image will be larger; if shortened, and the object carried a little away from the lense, smaller.

Its brilliancy is greatly increased if the sunlight is condensed upon the object by means of a lense; one about two inches in diameter and three or four inches focal length answers the purpose well, always being careful not to exactly focus the sunlight upon the object, if so it would be injured by the heat.

An opaque microscope is easily made by condensing sunlight upon the side of the object nearest the little magnifying lense, instead of letting the light pass through the object as in the former case.

By this most simple means it is in the power of every daguerreotypist to greatly aid the naturalist in his researches, giving him in a few moments drawings of invisible objects penciled by Nature's own hand, which it would be impossible for him to obtain in any other way, and he also possesses himself with an invaluable collection of natural objects that would be of great interest to the public.—John A. Whipple, No. 96 Washington st. Boston. Oct. 7th, 1852.


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