This instrument was found at my grandfathers house several years ago, and we are wondering what it is. All we know is that it is some kind of scientific instrument, possibly some kind of clinometer. It has at least two mirrors/lenses inside that it looks like you can make some kind of angle with, and on the inside of the cap there is a table of tangents. There are two additional lenses with red and green glass. Ideally, we are looking to find out what this is, how it was used, and if it is worth anything. In case you can't read the inscription from the pictures, it says Newton and Co, London, No 511, 1915.
Thanks!
