Fig. 57.
Fig. 58.
Note 199, pp. [171], [200]. Fig. 58 shows Newton’s rings, of which there are seven, formed by screwing two lenses of glass together. Provided the incident light be white, they always succeed each other in the following order:—
1st ring, or 1st order of colours: Black, very faint blue, brilliant white, yellow, orange, red.
2nd ring: Dark purple, or rather violet, blue, a very imperfect yellow green, vivid yellow, crimson red.
3rd ring: Purple, blue, rich grass green, fine yellow, pink, crimson.
4th ring: Dull blueish green, pale yellowish pink, red.
5th ring: Pale blueish green, white, pink.