Steven Connor at Cabinet Magazine:
The strangeness of electricity seemed to be that it was at once “so moveable and incapable of rest” and yet also capable of being arrested if deprived of a suitable conductor, for example, by the air. This latter had been demonstrated most dramatically by the experiments of Stephen Gray in the early 1700s, who had electrified charity boys, an ample supply of which was furnished by Charterhouse where he was resident, hung from silken cords in mid-air. The sense that electricity belongs naturally to “the more hidden properties of the air” is borne out by the fact that so many demonstrations and depictions showed electrified subjects who were themselves suspended in midair (even though the reason for this is actually to use the air as insulation). Charles Burney, the father of the novelist Fanny, recorded in 1775 his terror at being caught in a thunderstorm in Bavaria, and his wish for a bed off the ground, so he might sleep in safety “suspended by silk cords in the middle of a large room.”
more here.