This is a nice antique miniature kerosene lamp in silver mercury decorated glass with a clear glass chimney in the Acorn pattern by the Beaumont Glass Company.  The lamp measures 3 1/2" in height to the top of the font and 7 3/4" in height if you include the clear glass chimney.  The pattern is pictured in the Smith - Miniature Lamps I Book on page 78 Fig. 121.  Condition is excellent with the silver mercury decoration showing considerable wear in spots and the clear glass chimney being cut crooked at the base.