We were intrigued by scales that measured in drams. According to https://en.wikipedia.org/wiki/Dram_(unit) the unit appears to have started life as a coin/weighing mass in ancient Greece and will therefore be related to the drachma currency. It was taken up by apothecaries, hence its display in the window of a chemist's shop and made it into avoirdupois system, which is pounds and ounces. I thought that was the Imperial system but I think the Imperial system adopted the earlier avoirdupois and standardised it a bit more. Anyway, under that system, a dram became 1/16 ounce.