The variation of refractive index with density has been the subject of much experimental and theoretical inquiry.
It must evidently diminish as the refractive index increases.
Where the surface was hard and dense, Brewster found the refractive index to approach that of semi opal.
Its refractive index at the boiling-point has theoretically the value 1.11.
The refractive index of gypsum is 1.54, but heat none, being opaque.
The effects so produced are the differential results of the change of figure and of refractive index.
Generally the two spherical surfaces enclose a glass lens, and are bounded on the outside by air of refractive index 1.
Although the ratio of the sines is constant, the refractive index varies in different media.
Perhaps the surest single method of distinguishing precious stones is to find out the refractive index of the material.
Unlike other cubic crystals, diamond experiences a diminution of refractive index with increase of temperature.
refractive index n.
Abbr. n The ratio of the speed of light in air or in a vacuum to the speed of light in another medium.