In the 1750s the Society offered a premium for an improved hand mill. It might sound mundane but it served an important social purpose.
Much in keeping with today's ethos of pursuing inclusive growth: the hand mill would break the monopoly of one of the eighteenth century's most hated figures, the miller. As the astronomer James Ferguson put it:
"The poor people of this country have been long abused by the millers, who would not grind their corn, but forced them to give theirs in exchange for meal so adulterated, as has been proved to be slow poison."
The Society's response was to offer £50 for a mill cheap enough to be distributed free of charge to poor people to grind their own corn. It's not clear how successful the prize was, but in response to it the Society received model hand-mills from some of the keenest mechanical minds of the time, particularly John Harrison (most famous as the inventor of the marine chronometer, for accurately determining longitude at sea).