I have 2 ideas, but have some questions first: #1 Does it pump; meaning does the small part goes into the larger part? #2 Does the smaller handle lock the larger handle? #3 What does the large end look like; is it open and/or threaded?
with such a nice box being made to fit and all.....i am thinking there must be some writhing on the lid or engraving on the tool......better pics would be nice too.
Since it is brass and in a wooden box with a velvet lining, I think it is either nautical or medical. If it is nautical, it looks to be a bilge pump. If it is human medical, it appears to be enema related.
It has the shape of a barrel pump, but I don't think barrel pumps would be sold/bought in a velvet lined box. During the mid-1800's+ most brass items that were 'specially' boxed were either nautical or medical. (As soon as I typed that last sentence, I thought there will be at least one strange object that is NOT nautical or medical that is brass in a fancy box. )
Maybe I should have said, brass items shaped like that . . .It maybe some type of precision tool. I'd like to see better pics and get more info from the museum.