Possibly a Nordenfelt third series 1" single barrel gun.
Doesn't actually look like any of the anti-torpedo boat guns used by UK, or any of the common 1" cannon of that era (Hotchkiss, Vickers, Gardner, etc). What was the approximate calibre/ whereabouts is it/ did the makers plate say anything apart from the number?
[TD="colspan: 2"] Brass 1905 Naval Cone Mount
Rarely offered for sale; 1905 dated bronze USN deck cone for the USN One Pounder 37mm gun of the Spanish American War period. Excellent original condition; The base is 24" across and it stands 40" tall. Nicely marked on the top rim as the photos show. Original data plates are in still intact. Freight costs would be around $250 however I would only charge the actual cost. I have an account with Old Dominion Freightlines so can get a really great rate.