J.F. Mascher
1855, May
Mascher's Stereoscopes

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Published in "American Journal of Science and Arts", Second Series, Volume XIX, May, 1855, p.447.
 
1. Mascher's Stereoscopes. The annexed figure is a perspective view of a very ingenious application of the stereoscope to daguerreotype medallions. A patent for this improvement has been recently granted to J. F. Mascher of Philadelphia. Attached lo the main central rim of a locket, there are two lids with daguerreotype pictures on them; these lids are hinged on each side of the rim. There are also two supplementary lids, each containing a lens, which are also hinged to the rim as shown, but are fitted to fold within the picture lids, and are arranged in such relation to the same, that upon being opened and properly adjusted, the lenses will stand opposite to the pictures, and convert the medallion into a stereoscope, by which a person looking through the glasses, will see but one picture, solid and life-like. The patentee has applied double convex lenses to these medallions the sides of which are of unequal convexity (as one to six) according to Brewster, so that the picture is rendered very clear. A medallion of this character can be used for a microscope and sun glass, and thus it can be carried around in the pocket, both as an ornamental and useful memento of affection.
 
More information may be obtained by letter addressed to J. F. Mascher, No. 408 North Second street, Philadelphia, Pa. Sci. Amer.
 
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