558 



TABLE 594.— SODIUM CHLORATE; QUARTZ 



TABLE 595.— REFLECTING FACTOR OF METALS (See Table 584) 



The surfaces of some of the samples were not perfect so that the corresponding values have less weight. The 

 following more recent values are given for tungsten and stellite, an exceedingly hard and untarnishable alloy 

 of Co. Cr, Mo, Mn. and Fe (C, Si. S. P). 



TABLE 596.— OPTICAL CONSTANTS OF METALS 



Two constants are required to characterize a metal optically, the refractive index, n, 

 and the absorption index, k, the latter of which has the following significance : the ampli- 

 tude of a wave after traveling one wavelength, X x measured in the metal, is reduced in the 

 ratio 1 : exp ( — 2wk) * or for any distance d 1 : exp ( — 2vdk/\ 1 ), for the same wave- 

 length measured in air this ratio becomes 1 : exp ( — 2wdnk/\ 1 ), nk is sometimes called 

 the extinction coefficient. Plane polarized light reflected from a polished metal surface is 

 in general elliptically polarized because of the relative change in phase between the two 

 rectangular cojnponents vibrating in and perpendicular to the plane of incidence. For a 

 certain angle, <p (principal incidence) the change is 90° and if the plane polarized incident 

 beam has a certain azimuth f (principal azimuth) circularly polarized light results. 



k = tan 2^ (1 — cot V) and n = 



sin <p tan <t> 

 (! + *•)* 



(1-Mcot 2 0). 



(continued) 



SMITHSONIAN PHYSICAL TABLES 



