A burning glass or burning lens is a large convex lens that can concentrate the sun's rays onto a small area, heating up the area and thus resulting in ignition of the exposed surface. Burning mirrors achieve a similar effect by using reflecting surfaces to focus the light. They were used in 18th-century chemical studies for burning materials in closed glass vessels where the products of combustion could be trapped for analysis. The burning glass was a useful contrivance in the days before electrical ignition was easily achieved.
Read more about Burning Glass: History, Current Use
Famous quotes containing the words burning and/or glass:
“But must I confess how I liked him,
How glad I was he had come like a guest in quiet, to drink at my
water-trough
And depart peaceful, pacified, and thankless,
Into the burning bowels of this earth?”
—D.H. (David Herbert)
“It is difficult to read. The page is dark.
Yet he knows what it is that he expects.
The page is blank or a frame without a glass
Or a glass that is empty when he looks.”
—Wallace Stevens (1879–1955)