I have recently acquired an optical instrument which appears to be a
It is labelled "Watson x2 patent pending"
it has a 10x microscope eyepiece looking at a square graticule, and an
optical input via a long black bakelite cone which clearly drops into a
tube, possibly a microscope.
Inside are some very high quality optics dividing the beam with a 45degree
dichroic mirror, creating two alternate paths, one green, one red.
A very accurate micrometer slides two mirrors to vary the two path lengths.
A counter-type mechanical readout gives readings from about 0 to 110, the
path lengths being equal (interference fringes visible) at around 40 units.
Slide travel is about 4mm with readout to 0.05 units easily ie one part in
It is in a cream enamelled body.
Anyone any idea what it is ?
Thorough internet search reveals nothing