Note 49 — Chapter VI

Experiments on the influence of heat on differently-coloured bodies were first made by Dr. Hooke; and it was not until long after that Franklin made his ingenious experiments. Davy exposed to sunshine six equal pieces of copper, painted white, yellow, red, green, blue, and black, in such a manner that one side only was illuminated. To the dark side he attached a bit of cerate, ascertained by experiment to melt at 700. The cerate attached to the black became fluid first, the blue next, then the green and red, and lastly the yellow and white.—Beddoes’s Contributions to Physical Knowledge, and collected works of Sir Humphry Davy, vol. ii. p. 27.