Obviously nowhere near difficult enough - Steven is correct with spirit measure, although I think this one is more interesting to us than the usual modern metal cups - it is in fact a quarter gill measure.
Apparently the 1⁄4 gill was previously the most common measure in Scotland, and may still remain as the standard measure in pubs in Ireland - although I think most measures are now based on metric equivalents
. It seems that in England we had a smaller spirits capacity of one sixth of a gill.
Around the top of this example is engraved '1/4 gill' - (with Steven's line), and the dark blob is in fact a lead seal which goes penetrates the thickness of the glass and is stamped on the outside with a crown followed by ER and the no. 35. However, of most interest is the engraving around the lower portion which says "Richardson's Patent B623". There is slice cutting round the neck and punties around the base, and it stands 3.3/4" tall - most of the base is taken up with the ground/polished pontil depression. The script is quite florid, and looks earlier than I'd associate with Elizabeth's reign.
Anyway, just thought it was interesting, and if anyone wishes to add anything please feel free.
P.S. commiserations to Carolyn and Keith