Here we have one of a matched pair of 1880s signed J. Tams Imperial Measure drinking vessels.  This is a one pint size tankard.  The tankard has an ingenious leveling feature to guarantee the same pint measure of beer or ale poured every time, which is a hole near the rim, punched in the clay before firing, that connects to the top of the handle.  The bar tender would fill the tankard to the level of the hole, any excess liquid would drain away, guaranteeing the same measure every time.  The front of the mug has a bold, prominent stamp reading: “1. PINT / IMPERIAL / STAMPED REGULATED / MEASURE / PATENTED MARCH 31, 1882. BY / J. TAMS. LONGTON. STAFF.”   The mug is wider at the base, tapering to the opening with blue and rust brown bands at the rim.  The underside has a lead imperial seal inserted into a recess and is impressed with a crown and “VR”.   Photographs of the leveling feature and lead imperial seal are included in “MOCHA and related dipped wares, 1770-1939” by Jonathan Rickard on page 58.  Measuring 4 5/8” in height, the mug has a line in the rim near the handle and one the inside, there is also minor glaze wear on the edge of the handle from use.  This is an extremely rare mug that would be an important addition to any collection.