Thanks again, Apo.
I found an on-line source of catalogs and manuals for the 40’s and 50’s DynOptic Scopes which comprise the bulk of my B&L collection, but I’ve only seen 2 catalogs for the late 19th and very early 20th Century.
Weren’t they the top selling microscopes for a time? Seems like there would be documentation out the wazoo, but if there is, no one is sharing.
Bausch & Lomb made the claim that they were the largest microscope company in the world around the turn of the century/ By the early part of the 20th century they had their own glass plant in Germany and had an interest in Zeiss. Yet, by the early 1920's Spencer seems to have been dominant in the U.S. What happened? W.W. I, probably ; the conditions of which were not very favourable to B & L, with their association with Zeiss. Their involvement with Zeiss collapsed, fairly quickly and they had to establish their own patents. The glass factory had disappeared by the war's end. After the war, the list of foreign offices in their catalogues, does not include one in Germany, so something serious happened; most likely patent violations.
B & L was a little slow to manage their equipment lineup in order to meet the post W.W. I world. In 1919, there still was no binocular microscope, although they had a fully competitive monocular research model, the DDS, which could be had with apochromats. The monocular was still the choice of researchers but Spencer by 1917, had the binocular models 1 and 2, with facility to close off either the left or right optical path for monocular viewing. Later , they introduced a sliding binocular head, that allowed for a straight through, monocular pathway.
By 1922, B & L were offering a line of microscopes(CAE,CBE,CDE and FAE), which had interchangeable monocular or binocular bodies but by then, Spencer had a considerable lead in appealing to the obviously burgeoning hunger for binocular lab microscopes. B & L really never got it back until the Balplan came along, which briefly eclipsed Spencer's domination of the lab microscope market in the U.S.
I don't see many catalogues around for B & L either. It was even hard to find much for the Balplan! I have the one research microscope catalogue, which I have yet to scan but I did copy some pictures. I think you have seen those viewtopic.php?f=15&t=2215&hilit=b+%26+l+research+catalogue
but I will try to do a complete scan in the near future.
I think I posted this site too. https://babel.hathitrust.org/cgi/pt?id= ... 1up;seq=38
, which you probably already know. I count, 10 catalogues in this collection, between 1896 and 1929. From the 1896 catalogue( Bausch & Lomb's 15th), your microscope is a MODEL, model, or an F, specifically an F4, due to it having the double nosepiece. I don't know of any earlier Bausch & Lomb catalogue.