Some additional info regarding Alan Feldman's loupe.
The earliest mention of this "Binocular Magnifier" in my reference material is from 1911 but it certainly could have been produced earlier. The magnifier was offered in IP sizes of 59, 62, 65, and 68 mm. In Alan's photo you can see that his is marked as a 62mm model. Available magnifications are listed as 3X, 2.5X, 2X, 1X and 0.75X . The shiny pin visible in Alan's center photo is designed to hold a series of attachments specific to different applications. For example, my 1911 catalog shows an illuminator, a reflective mirror with two holes to allow examination of the eye and a bench stand onto which the loupe could be mounted for examining specimens.
Also available were special spectacle correction lenses to fit into the eyecup and an accessory lens set to modify the magnification.
The complete set with headband, case, light, battery holder carried the code word Lascabais and sold for 64.50 Marks in 1912. The magnifier alone was Lasagnone and sold for 36 Marks.
Subject: About the names of some Carl Zeiss binoculars
From: Lothar Helling <L.Helling@___ne.de>
The prefix "Del" could mean "Delta" = angle. All the models with "Del" are wide angle models.
> Delturis 8x24 and Delturisem 8x24
> Deltrentis 8x30 and Deltrintem 8x30
> Delactis 8x40 and Delactem 8x40
>And what about the common prefix "Del-". What should it mean?
Subject: Flakfernrohr article
In case you haven't seen it, there is an informative article on cloudynights.com on restoring a 10x80 flakglas:
This is a good article, although some of the procedures would be detrimental to optical performance:
"cerium oxide glass polishing compound used by car window repair shops. The orange-brown powder mixes with water to form a non-toxic paste which Delta Kits recommended applying with a circular cloth drill attachment. I decided to see how rubbing the prisms with a rag soaked in the paste and wrapped around a finger would work before I resorted to power tools on the prisms. After about 5 minutes of hard rubbing, I saw a noticeable difference. After 10 minutes the first prism looked almost as good as new. After working on both prisms for awhile longer, there was still some faint staining that looked like tarnishing, but the difference was like night and day. The faces of the prisms are a bit wavy looking in the places where serious rust deposits etched them, but they both now perform much better than I had ever hoped they would."
Binocular List #287: 23 Feb. 2004
Subject: Zeiss Binocular Model Identification