BREWSTER, DAVID. - ON BIFRINGENCE IN GLASS.

On new properties of heat, as exhibited in its propagation along plates of glass. Read January 11, 1816.

(London, W. Bulmer and Co., 1816). 4to. No wrappers as extracted from "Philosophical Transactions" 1816 - Part I. Pp. 46-114 and 4 engraved plates. A small brownspot outside image in right margin of plates. Clean and fine.

First printing of an importent paper in the history of optics describing the photoeleasticity of glass.
In the paper Brewster describes numerous investigations of birefringent glass. While Seebeck related birefringence of glass to its internal structure, Brewster considered heat as the cause of birefringence. The paper is a very thorough investigation of refringence in glass with numerous examples. To illustrate, Fig. 3 shows photoelastic patterns of a thick quadratic plate. Brewster actually comes close to the real reason of birefringence in glass: "I have discovered that glass, and all other substances that have not the property of double refraction, are capable of receiving it from mechanical pressure, and that a compressing force always produces the structure which givesthe exterior fringes in crystallized glass, while a dilating force produces the structure which develops the interior fringes." Brewster suggests that glass should be carefully examined by polarized lightbefore it is purchased.

Together with the Brewster-paper comes a paper by John Frederick W. Herschel: "On the development of exponential functions; together with several new theorems relating to finite differences." Pp. 25-45.

Order-nr.: 42801