A comment about my recent blog about how the glass that we often call a tumbler was so named was a pleading comment indeed. "You can't stop there," it said. "You can't leave us hanging!"
The comment referred to the fact that originally, beverage glasses called tumblers had a pointed or a convexly rounded bottom - hence, I assumed, the name "tumbler." (You couldn't put it down without it falling over.)
Well, OK. I took out the heavy guns and consulted the Oxford English Dictionary. According to the OED, the whole idea of the shape was "so that it could not be set down until emptied." I guess toasts could not be satisfied with a mere sip. The definition also mentioned that such cups "were often of silver or gold."
The first citation was dated 1664, but I was surprised to see that pointed or rounded tumbler bottoms lasted quite a while. A citation from 1865: "Rings of pottery ... evidently intended to serve as supports for these earthenware tumblers." And from 1876: "The guests were supplied with tumblers or glass vessels which, being rounded at the base, could not stand upright, and must, therefore, be emptied at a draught."
More alarmingly, perhaps, it turns out that there was a related meaning. A tumbler also could be "a toy, usually representing a grotesque squatting figure, having the center of gravity low and the base rounded so as to continue rocking when touched." A citation from 1851: "Her legs tucked up mysteriously under her gown into a rounded ball, so that her figure resembled in shape the plaster tumblers sold by the Italians."
I think I can stop here.