On the refraction and dispersion of neon

Abstract

By the kindness of Sir William Ramsay and Mr. H. E. Watson we have had an opportunity of measuring the refractive index of neon with a large quantity of the gas (300 c. c.) which had been carefully purified by Mr. Watson. Subject to small corrections which he has not yet completed, the weight of 1 litre of the gas was 0·9005 gramme at 0° C. and 760 mm. pressure in London. From 11 experiments which hardly varied by 1 part in 500 we find the refractive index at 0° C. and 760 mm. for the green mercury line (λ = 5461) to be 1·00006716 or, doubling for comparison with diatomic gases, 1·0001343.