Hand spectroscope

Beck, London
Black lacquered hand spectroscope 20 cm long closed 21,5 when pulled out and just under 2,5 cm in diameter. As well as producing the spectrum the slit also appears as a bright line. Turning the knurled knob at the side of the instrument moves the spectrum across the field of vision whilst the bright line stays fixed. It is in his original blue velvet and blue silk fitted case
Signed: “BECK | LONDON “ early 20th century.

private collection