Crystal and leather; L. 4 1/2 in. (11.4 cm), W. 2 5/8 in. (6.7 cm), D. 3/8 in. (1.0 cm)
Atwater Kent Museum of Philadelphia, The Historical Society of Pennsylvania Collection (Philadelphia, Pa.), HSP.C.1.7
This "burning glass" is a convex lens that will concentrate the beams of light, and raise the temperature of an object beneath it until it bursts into flame.