468 E.. S. Holden— Components of Binary Stars. 
enough knowledge to say. The following extracts seem, how- 
ever, to be worth recording in this connection : 
‘Since spectrum-analysis shows that certain of the laws of 
terrestrial physics prevail in the sun and stars, there can be 
little doubt that the immediate source of solar and stellar light 
must be solid or liquid matter maintained in an intensely 
incandescent state, the result of an exceedingly high tempera- 
Or Gin. We The light from incandescent solid or liquid bodies 
affords an unbroken spectrum containing rays of light of every 
degree of refrangibility within the portion of the spectrum 
which is visible. As this condition of the light is connected 
with the state of solidity or liquidity and not with the chemical 
nature of the body, it is highly probable that the light when 
first emitted from the photosphere . . . . would be in all cases 
identical. The source of the differences of color, therefore, is 
to be sought in the difference of the constituents of the invest- 
ing atmospheres.”* 
This conclusion, that the characteristic colors of stars are 
data in the case before us. The statements in italics seem to 
me of interest and importance, and they are borne out by the 
* Huggins and Miller, on the Spectra of some of the fixed stars: Phil. Trans. 
1864, p. 429. 
+ For example, Admiral Smyth calls a Lyre a “ green” star. 
