robert temple--ice lens

''chinese optics is also discussed by jin quipeng, ... in his essay, jin quotes zhang hua of the jin dynasty (265-420 ad) in his book record of the investigation of things; 'cut a piece of ice into a sphere, lift it in the sun and let its shadow fall on a piece of moxa [tinder made from an artemesia related to wormwood]; the moxa will be set alight'. this is the earliest surviving record which i have found of ice being cut to make a burning-lens; later in the book we encounter a frenchman who did the same thing in the 18th century.''

robert temple, the crystal sun; section 2, chapter 2, note 13.

ice camera at youtube.