LXXIII. An investigation of the optical properties of films of magnetic metals

io'a " t "THE ob]ect of this invest ~, tlon was to s udy the magnetm J_ rotation and ellipticityproduced in plane-polarizedlight by fihns of magnetic metals, alot~g with other properties intimately associated in theory with these--namely, the refr:lctive indices and extinction coefficients.That a thorough investigation of this kind would prove fruitful seemed evident from the results obtained in this laboratory by W. D. Harris Jr, who found that iron films, obtained by cathode deposit in a glow current, exhibited magnetic effects differing with the gas in which they were produced.His results also show that the variation in the magnetic rotation of these fihns with the wave-length of light is strikingly different from that obtained by Lobach $ for electrolytic iron 9After improving the optical system used by Harris, we have been able to extend observations on these films into the region of relatively greater absorption, which this type is found to possess.