I found this one in New Hampshire about 25 miles from North Hampton, the home of the Samuel D. Lane who signed it, close to two centuries ago I believe. I've seen powder horns carved into like scrimshaw (which I always covet) and plenty with hand-carved wooden plugs at both ends, but I've never seen one  (beautifully) signed on a circle of laid paper, with hand-cut glass over top. I presume it was done as a sort of commemoration by Lane himself, I would think retiring it after use in battle. The Lane family was a prominent one in New Hampshire--I believe this Samuel D. Lane (1809-1895) was the nephew of Samuel Lane (1718-1809) whose diary kept over 60 years was published ("The Years of the Life of Samuel Lane, 1718-1806: A New Hampshire Man and His World" and provides and important account of the life of a colonial New England artisan and tradesman. To me the writing (and paper) here looks c. earlier 19th c. than later (and the circular penmanship makes me think of love tokens of the 1830s or so)--but I suppose not impossible that the battle in question was the Civil War. A piece of New Hampshire history for sure, and quite a beautiful, resonant object too I think, with an elegant shape to the horn, wonderful patina, and I love the idea of a handwritten plug at the end of a horn once used for storing gun powder, elegantly and forever putting it to rest. 

13 3/4" l measured on the square; 2 3/4 d at opening. Sits 3 3/4" t. Very good antique condition, with one small hairline split to the horn at the opening end, minor and stable and I don't think at all detracting.