alum-cell

Updated: May 22, 2025

Placing the alum-cell again in front of the electric lamp, we assure ourselves, as before, of the utter inability of the concentrated light to fire white paper-Introducing a cell containing the solution of iodine, the light is entirely cut off; and then, on removing the alum-cell, the white paper at the dark focus is instantly set on fire.

John Tyndall - Six Lectures on Light: Delivered In The United States In 1872-1873

Here is a large flask containing a freezing mixture, which has so chilled the flask, that the aqueous vapour of the air of this room has been condensed and frozen upon it to a white fur. Introducing the alum-cell, and placing the coating of hoar-frost at the intensely luminous focus of the electric lamp, not a spicula of the dazzling frost is melted.

John Tyndall - Six Lectures on Light: Delivered In The United States In 1872-1873