What is "oxycalcium light"

Drummond light \Drum"mond light`\ [From Thomas Drummond, a British naval officer.] A very intense light, produced by turning two streams of gas, one oxygen and the other hydrogen, or coal gas, in a state of ignition, upon a ball of lime; or a stream of oxygen gas through a flame of alcohol upon a ball or disk of lime; -- called also oxycalcium light, or lime light.

Note: The name is also applied sometimes to a heliostat, invented by Drummond, for rendering visible a distant point, as in geodetic surveying, by reflecting upon it a beam of light from the sun.

n. limelight