I have recently acquired an optical instrument which appears to be a
microscope accessory.
It is labelled "Watson x2 patent pending"
and "W.I.S.E."
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
two thousand.
It is in a cream enamelled body.
Anyone any idea what it is ?
Thorough internet search reveals nothing
