What is this

[AlexS]

Diagram as promised.

Does it have a maker's name on it. It appears to be a good quality one, with a lens to read the vernier scale.

Cheaper ones did not have an adjustable scale, could only be used to set out an exact right angle. That one could be used to measure an angle that may not have been exact.

[macca2]

No unfortunately there is no inscriptions at all on this one, which is a bit of a worry as I would think anything worthwhile would have the makers name etc.

They are described in some sites on Google as being able to beheld vertical instead of horizontal and used as a sextant???????????
thanks macca.

[fred.n]

pocket sextant??
would that be called a compass??
You place it on top of a map to get detailed bearings to a "position"??
then march on, and on. and on

[arose62]

Found this (whilst googling for "how to velvet line a box with fitted cut-outs")

http://www.stanleylondon.com/sext-box.htm

This "Box or Drum Sextant" looks pretty close to yours. Maybe another set of search terms to google over ?

Cheers,
Andrew