No. 2 Euryscop
(6½x8½ - 8x10) on an American
Optical St. Louis Variation 2.1
Voightländer & Sohn lenses were commonly offered as an upgrade to house lenses (e.g., Rochester Single Achromats).
The name Euryscope: Voightländer apparently used the brand name Euryscope for most if not all of its lenses; it may be their name for a rapid rectilinear lens.
Various series of lenses were offered, each series representing a different lens formulation. In all series, lenses have a number - the greater the number, the longer the focal length, as was usual for almost all photographic lens manufacturers. In some cases, a letter is used to distinguish between series. For example, Indermill's catalog, above, shows an Improved Euryscope series (on the left) which appears to be a rapid rectilinear, and also seems to be identical (in appearance) to the Euryscope No. 5 photograph, above. On the right, a Euryscope, otherwise un-named, is said to have a slightly changed formula, and its lenses are designated 1A, 2A, 3A, etc. The same engraving is used to illustrate both series.
Over time, the formulation within a given series could change. Between 1885 and 1894, the formulation of the plain 1, 2, 3, etc. Euryscopes changed - in 1885, the No. 5 has a 17.5" focal length, while in 1894, the No. 5 has a 14" focal length (see above).
References:
My No. 7 Catalogue, T. F. Indermill, St. Joseph, MO, October 1,
1885, p. 88
An
Illustrated Catalogue of Photographic Cameras, Lenses and Other
Apparatus and Materials for Photography, W.H. Walmsley & Co.
(Philadelphia, PA), April 1, 1888, p. 44
Illustrated Catalogue of Photographic Apparatus,
Rochester Optical Co., Rochester, NY,
June 1890, p. 35
The
Internation Annual of Anthony's Photographic Bulletin", Vo. IV,
June, 1891, E. & H.T. Anthony & Co. (New York, NY), ads p.42
1892 Illustrated Catalogue of Photographic Apparatus,
Rochester Optical Co. (Rochester, NY), 1892, p.
45
1894 Catalogue of Photographic Apparatus, Rochester Optical Co.
(Rochester, NY), 1894, p. 62