The refractive indices of the elements.

Abstract

In a letter addressed to ‘Nature,’ in October, 1902, attention was drawn to the fact that the refractivities of the five inert gases of the atmosphere, He, Ne, A, Kr, and X, as determined by Ramsay and Travers, were, within narrow limits of accuracy, in the proportion of 1, 2, 8, 12 and 20; or, more simply, of 1/4,1/2, 2, 3, and 5.

Refractive index and dispersion of liquid hydrogen

“…The Landolt-Bornstein tables [5] give extracts of much of the published data on gaseous hydrogen. Additional references are given in a compilation by Maryott and Buckley [6], There are five sources of data in the visible and ultraviolet, of which four are in excellent agreement: Cuthbertson and Cuthbertson [7], Koch [8], Kirn [9], and…”

“…(7) This permits the density dependence to be separated from the dispersion in the term, r ; i.e., the coefficients, A and B, are treated as independent of density. Equation (7) was fitted to the average of the smoothed refractive indices of Koch and Kirn at the two mercury lines used in nearly all of the various investigations, 4358 and 5461 A, and at A. = °°.…”

“…If these data are fitted by the Cauchy formula (7), further evidence of imprecision is found, namely that the coefficient B is negative.…”

“…Equate this to r by Maxwell's relation (4). Use the accurate formula (7) for dispersion of the gas at STP to convert this to values of r, at the desired wavelengths. The final step is the same as in procedure (a).…”

“…This impression is supported by the appearance of figures 1 and 2, including the fact that the curvature in figure 2 is of physically realistic sign. Hence the three-term dispersion formula (7) could be used to fit his data. Another evidence of the quality of this work is the fact that the saturated liquid density as determined by Augustin in a separate experiment is within 0.…”