HISTORY OF THE NELSON-CURTIES MICROSCOPES

MAKER: CHARLES BAKER COMPANY

THE SECOND 'NELSON' MICROSCOPE (LATER THE NUMBER 2 MODEL)

The next year, in 1888, the first versions of what came to be known as the 'Nelson' Microscope were described. This stand, later to be called the 'Nelson-Curties No. 2', or simply the 'Nelson Model', was, for a few years, the 'No. 1' stand for the Baker company. This early version of the No. 2. was referred to in the JRMS as the 'Nelson-Curties (Large Model)'. In modern times, this stand is often called the 'Nelson-Baker' to differentiate it from Nelsononian stands made by other makers. One of the important features of this microscope was the presence two fine focus controls, one for focusing the tube and the other for focusing the substage. This feature is needed if one is going to use Nelsonian Illumination, also called Critical Illumination. It was first reported only in written form in the JRMS of 1888 on page 691 and was subsequently first pictured in the JRMS of 1889 page 801. The microscope, as pictured in the 1889 JRMS differed from the later number 2 in the following ways. First, it had a concentric controlled mechanical stage which did not interpose a second plate on which the slide moved, but rather moved only the slide holder(after Mayall's design). Many later versions had two separate controls for movement as seen in the later No 2 and even some No 1 microscopes. Secondly, it had round feet without slots(to be added in later models), and third, the substage fine adjustment was initially standard rather than an option as it was later. Fine adjustment both above and below the stage used the 'Campbell Differential Screw' mechanism as noted above.