Watson Van Heurck Circuit Stage Binocular Microscope

English, c.1910, engraved to the rear of the stand 'W. Watson& Sons, Ltd, 313 High Holborn, London, 38737' and to the bar 'Circuit Stage Van Herurck', the microscope on a massive Black lacquered brass tripod foot, with brass pad feet, at the top is a large friction locked trunnion that supports the main body of the microscope, at the bottom is a large plano-concave mirror in a gimbal, above this is the fully mechanical substage with X-Y control, rotational control via a gear and pinion, all with rack and pinion focusing, full mechanical circuit stage with Turrel type adjustment with vernier scales, with retro fitted micro forge (which can be fully unclipped and unscrewed) limb incorporating fine focus control with course rack and pinion to the rear of the bodytube, the monocular body tube with a racked drawer tube and push/pull drawer tube, the binocular body with inter-ocular rackwork and engraved 'High Power Binocular Eyepiece', in the original French polished mahogany cabinet with two drawers of accessories, the first containing:

2mm Apochromatic objective by W. Watson & Sons.
4mm Apochromatic objective by W. Watson & Sons.
8mm Apochromatic objective by W. Watson & Sons.
16mm Apochromatic objective by W. Watson & Sons.
1 1/2" Holoscopic objective by W. Watson & Sons.
3" Holoscopic objective by W. Watson & Sons.
x5 Holoscopic eyepiece by Watson.
x7 Holoscopic eyepiece by Watson.
x20 Holoscopic eyepiece by Watson.
Pair of binocular Eyepieces.

smaller drawer contains:

x10 Holoscopic eyepiece by Watson.
Pair of binocular Eyepieces.

All in a large French polished cabinet

Provenance: this microscope belonged to Dr. Kenneth I. Johnstone, B.Sc, Ph.D, M.B, Ch.Bb(Leeds) F.R.M.S., A.R.P.S. he was known for his contributions to microbiology and specifically for his work on micromanipulation techniques involving bacteria. His book titled "Micromanipulation of Bacteria" is an authoritative resource in this specialized area of research. In this book, Johnstone discusses various techniques for manipulating microscopic organisms, including the use of a microforge.

A microforge is a precision instrument used in biological laboratories to modify microtools under a microscope. It typically involves a heating element to melt and shape glass needles or other microtools, which can be used for handling microscopic samples such as single cells or bacteria.

Johnstone's work and his book are significant because they provide detailed methodologies for researchers working with microorganisms, offering insights into handling, manipulating, and modifying microscopic life forms for experimental purposes. This has applications in various fields, including microbiology, cellular biology, and medical research.