These values are closer to the Jena type O.144 glass than to other glasses in the 1902 publication and I believe that is in fact the exact type used for both of these prisms. The slight discrepancy in dispersion values (Abbe v number) is probably due to accuracy limitations in my measurement wavelengths. Someday I plan to repeat these measurements with a higher accuracy setup.
Note that modern Schott glass catalogs use a different wavelength for the nominal index of refraction measurement, Nd at 587.56nm Yellow Helium line, but the same wavelengths at F and C.
If anyone else has other data or measurements please let us know.
Subject: Zeiss prisms
Abbe used the new "specialy light and clear" Boro-Silikat-Kronglas from Schott for the first Zeiss binoculars.
Subject: 6x30 codes
From: "Prof GH Samuel" <g.h.samuel@___c.uk>
Fzg is not that rare a code: I have in my time seen about half a dozen 6x30's carrying it (and I own one whose optical quality is superb). However the serial numbers are always low: between 2000-4000.
Other 6x30 codes not listed in your last circular are:
emv: Hertel & Reuss
eug: Optische Prazisionwerke, Warsaw
fvs: Spindler & Hoyer
fvx: Beck & Sohne, Kassel
jxn: Helmut Korth, Berlin
I have personally seen 6x30 binoculars carrying these codes (or photographs of such binoculars). However by far the most common 6x30 codes are ddx and cag, but I have never seen these two codes on 7x50 or 10x50 glasses.
As a kind of answer to Mr. Tenenholtz view on logistics.
That is a classical dilemma...If you plan perfectly, everybody will have the best possible equipment at the appropiate time.
Only planners are human, and the world is too complex to be planned for.
In economics, I have heard it described as the inner friction of the system.
Friction is loss of energy and loosing something puts you at a disadvantage.