I’m something of a B&L enthusiast. The exact reason is manifold, but likely started with a proximity based loyalty and it being the brand of my first stand. Today something from a competitor. -K
The American Optical Corporation was once one of the leading optical firms in the United States, if not the world. Well, honestly they never got the sort of press enjoyed by Zeiss, B&L, or Lietz. If you haven’t heard of them no doubt you don’t collect microscopes, or you’re not in the US. Perhaps AO Spencer sounds more familiar? Spencer Buffalo? In any case one of their finest innovations was something they called the Micro-Glide Stage. A simple apparatus, well executed and versatile, it’s something a wonder that it never became more popular.
The concept is simple, incorporate a floating stage of large size and circular outline on an otherwise stationary stage. By virtue of a large central hole the upper stage may be moved around the optical axis without the tedious turning of milled heads required by mechanical stages, or the fine touch (which takes some time for the student to acquire) needed in manipulating slides directly. Having used such a stage one quickly becomes adept at orienting the desired portion of any specimen. Because the stage is moved, rather than the slide one has the added advantage of not worrying about an errant stage clip knocking a cover slip from a temporary mount while chasing an active organism about the field of view.
As one can see in this illustration taken from a maintenance pamphlet published by American Optical, the stage is almost supernaturally simple. No doubt the company used the simplicity of the Micro-Glide Stage to its advantage. Such an apparatus is far less complex than the circular mechanical stages seen on research microscopes, and would have provided American Optical a bit of an edge in marketing their microscopes to schools (an important client for nearly all manufacturers).
The utility of a rotate-able stage is not something one often has to convince a microscopist of, and no attempt will be made here to do so. Only, it has always been practice for schools (from grammar to graduate) to utilize a rugged and uncomplicated sort of microscope; it has however, been a rare thing for them to offer students the chance to use a rotate-able stage. For that reason alone many who use microscopes, even for professional reasons, have never made use of microscope bearing a rotate-able stage and will not feel the acute discomfort of lacking one.
While the great biological and petrographic stands with their finely machined circular stages are beyond the reach of most enthusiasts, or at least past the financial tolerance of spouses and parents, one can usually find an American Optical stand featuring a Micro-Glide stage for sale surplus or second-hand in the range of fifty dollars. At the risk of sounding the salesmen, I’d recommend searching one out. Below see a simple students model One-Sixty I prefer for looking at algae, living diatoms, rotifera, and all the bustle and huff in a drop of water.