The photograph of this piece of optical glass, Bausch & Lomb’s “Crown Jewel of Optical Science,” was extracted from a vintage Bausch & Lomb Ebay catalog of Balopticons and Accessories.
That Bausch & Lomb publication, auctioned in October 2007 on Ebay, states:
“This chunk of optical glass was broken out of the large ceramic crucible in which it was fired in the Bausch & Lomb glass furnaces.
“Within its irregular surface is crystal-clear homogeneous glass, critically precise in index of refraction, dispersion, and other optical and physical characteristics. From it will come lenses or prisms for Bausch & Lomb scientific instruments.
“Since the founding of the Bausch & Lomb Glass Plant prior to World War I, Bausch & Lomb glass technicians and ceramic engineers have dedicated themselves to the task of perfecting and producing glass of the highest quality—that Bausch & Lomb instruments may have the exact characteristics that performance intended by their designers.”
One of the vintage scientific products produced from high-quality Bausch & Lomb glass was the Bausch & Lomb No. 4115 Micro Projector, advertised in another one of their catalogs. This 1927 publication described the “Low Power Projection Microscope,” displayed in the photograph above, in the following words:
“REALIZING that many schools offering elementary courses in Biology have a real need for equipment with which to project microscopical slides of plant stems, flowers, insects, etc., we have developed a very simple and inexpensive projection microscope of high quality. Apparatus of this type is ordinarily too elaborate and expensive for high school use, and young students in Biology are therefore deprived of the use of this valuable and interesting method of study. Our newly designed simple projection microscope will very adequately fill this long felt need. While it has been especially constructed for use with our Balopticons B, C, and BC, it can be used regularly with any projection lantern having a projection lens with an outside barrel diameter of 2 ¼ inches, or by means of a special adapter supplied extra at a nominal cost, it can be attached to lenses of smaller sizes.
Bausch & Lomb Magic Lantern or Balopticon Model B
Bausch & Lomb Magic Lantern or
Balopticon Model BC
“This attachment is fastened to the front of the projection lens by means of a single clamp screw in such a way that one can quickly change from the projection of lantern slides to microscopical slides, no shifting of the projection lens being necessary. Slides are held in position on the stage by spring clips.
“The lens of this new instrument is of 2-inch focus, giving a magnification of 60 diameters at 10 feet, 120 at 20 feet and 180 at 30 feet, and is provided with a spiral focusing mount. A substage condenser of focus suitable for use with this lens, is permanently mounted with its upper surface flush with the stage.”
This low power projection microscope, as described above for lanterns having a projection lens of 2 ¾ inches in diameter, sold for $20.00 in 1927, according this publication—also auctioned on Ebay in 2007.
This page was last modified on Friday, August 20, 2010