A square, rosewood Travel Inkwell.
The turned inkwell cap has a brass ring fitted to its interior that locks to a corresponding brass ring with 3 teeth to the neck of the inkwell. The glass ink bottle is sat on a sprung pad to push it up against the cork lining to the lid interior to form a seal. Pushing the cap down and twisting locks the cap to the base.
The turned cap to the inkwell and the brass locking collars are nicely turned and well made. However, less trouble seems to have been taken over the square base of the inkwell. Only one of the four sides is polished, whilst there is a fine saw cut to the top of one edge whose side is not quite square. This suggests that it was perhaps meant to be fitted into something else or maybe had a brass (or other material) collar that tidied it up.
Coombs, Boynton & Finlay are an interesting company and their biography on our website is worth a read. There is a link under Literature. Circa 1835.