Eimer 901B, BHM 462.
41mm. Bronzed pewter. By R.Dumarest.
Obverse with draped bust of Boulton, reverse showing the methods used for coin and medal production at the Soho factory with each numbered circle on the reverse indicating how many coins of that diameter could be struck in one minute by eight of Boulton's presses.
Good Very Fine and very rare.
Ex James Watt Collection, Morton and Eden, 13/11/2002 (lot 249).