Sir Thomas Adams, former Mayor of London, died on 24 February 1668. Thomas Allen related to the meeting of the Royal Society on 27 February 1668 that a bladder stone taken out of the deceased weighed twenty-five ounces with a gutter in the middle, and that Adams did not experience discomfort from the stone. At the meeting on 26 March 1668, Allen produced the actual stone, which was weighed (and found to weigh 22 ounces and 3/8). Robert Hook was asked to measure it and draw a figure of it.