Index of Refraction of Nickel

The index of refraction, μ the extinction coeff., k; and the reflecting power, R, of electrolytic nickel were measured by R. S. Minor, F. Rother and K. Lauch, K. Lauch, H. Hauschild, A. de Gramont, M. Luckiesh, R. Hamer, I. C. Gardner, A. Kundt, M. Laue and F. F. Martens, P. Bergman and W. Guertler, F. Hlucka, A. Q. Tool, H. du Bois and H. Rubens, A. Pfluger, W. Rathenau, and E. Hagen and H. Rubens. The results of W. Meier for wave-lengths λ=589 to 668, for electrolytic nickel, and of G. Pfestorf for λ=578 to 254, are:

λ	668	589	578	436	406	366	313	254
μ	1.74	1.58	1.63	1.42	1.36	1.33	1.35	1.14
k	3.80	3.42	2.10	1.94	1.80	1.69	1.49	1.69
R	68.3	65.5	65.0	54.0	53.0	49.1	43.5	44.9 per cent.

The observations of G. Quincke for λ up to 527, 589, and 656, and of P. Drude for λ=589 and 630, and of M. Laue and F. F. Martens for λ=630:

λ	431	486	527	589	589	630	630	656
μ	1.40	1.54	1.63	1.74	1.79	1.89	1.99	1.93
k	2.49	2.90	3.11	3.39	3.32	3.55	3.95	3.83
R	53.3	58.6	64.5	63.4	62.0	63.7	67.6	66.8 per cent.

Observations were also made by H. von Wartenberg, M. Luckiesh, G. Pfestorf, P. R. Gleason, F. Henning, L. R. Ingersoll, C. Zakrewsky, and A. Q. Tool. I. C. Gardner studied the reflecting power in the ultra-violet; E. Hagen and H. Rubens, the variation of the emissive power with temp.; and E. Hagen and H. Rubens found for the reflecting power:

λ	251	326	385	420	550	770	800	5000	14,000
R	37.8	40.3	47.8	51.9	62.6	68.8	69.6	94.4	97.2 per cent.
	Ultra-violet			Visible			Ultra-red

The Reflecting Power of Nickel.

W. W. Coblentz and R. Stair found the reflecting power of chromium to be greater than that of nickel; and their results are summarized in Fig. The reflecting power of nickel in the ultra-violet was studied by R. Hamer. H. N. Edwards measured the total reflection of nickel films; H. Hauschild, C. A. Skinner and A. Q. Tool, and K. Kiessig, the optical properties of thin films of nickel. W. del Regno observed a break in the emissivity curve near 400°. L. Tronstad, A. H. Pfund, and E. Rupp studied the optical properties of nickel.

J. H. Gladstone gave for the refraction equivalent 10.4, and for the sp. Refraction, 0.177. W. J. Pope gave 12.84 for the refraction equivalent of nickel. H. Knoblauch gave 77.50 for the polarization angle for the ultra-red heat rays, and 70.00 for yellow light. C. J. Davisson and L. H. Germer studied the polarization of the reflected electron waves; W. Lobach, and A. Kundt, the electromagnetic rotation of the plane of polarized light; and L. R. Ingersoll, H. E. J. G. du Bois, J. G. Leathern, K. H. von Klitzing, A. Pietzcker, C. J. Gorter, E. Hirsch, W. Lobach, P. D. Foote, and C. Snow, the Kerr effect.