76 Intelligence and Miscellaneous Articles. 



red, yellow, and green bands; but the blue and violet part was divided 

 into a great number of equal and narrow bands. Leaving out these 

 bands (which might be invisible in the star), the spectrum of the 

 star strongly resembles that of the gas in the tube. I do not know 

 what the tube contained ; but I observed that the negative pole gave 

 the sharp spectrum of carbon, and that there was a black powder 

 near the electrodes. 



These phenomena favour the opinion of those who think that part 

 of the luminous and obscure bands of the celestial atmosphere is not 

 an effect of absorption, but a real radiation, as in the planetary 

 nebulse. 



The two coloured stars v of Bootes have given me almost conti- 

 nuous spectra, but in which the proportion of colours was different, 

 the red predominating in the red, and the blue in the blue. This 

 proves that these colours are not the effect of an optical contrast, as 

 many astronomers have supposed. — Comptes Rendus, June 5, 1865. 



ON THE WAVE-LENGTH OF THE BLUE INDIUM-LINE. 

 BY. J. MtTLLER. 



MM. F. Reich and Th. Richter of Freiberg having introduced 

 into the colourless flame of a Bunsen's lamp impure chloride of zinc 

 prepared from zinc-blende, and having examined the coloured flame 

 thus produced by means of a prism, observed a blue line which had 

 not previously been noticed. A closer examination showed that this 

 blue line belonged to a hitherto unknown metal, to which its discoverers 

 gave the name Indium, and concerning which they published further 

 details in Erdmann and Werther's Journal fur praktische Chemie. 



Professor Reich has been kind enough to give me a small piece 

 of metallic indium, as well as a small quantity of sulphide of indium 

 (which exhibits the spectral line of this metal in the most lasting 

 manner), in order that I might determine the wave-length of this 

 line. 



I have made this determination by the method and by means of 

 the grating which were first described in the first Part of the third 

 volume of the ' Reports of the Society for the Advancement of the 

 Natural Sciences' of Freiburg in the Breisgau,page 29*, and I thus 

 arrived at the following results : — 



Ind. a, 1, right 63 33 



Ind. a, 1, left 52 6 



whence x=b° 43''5, and X=0-0001995"'; 



Ind. a, 2, right 69 25 



Ind. a, 2, left 56 25 



whence we have t/=ll° 31 ''5, and \ = 0'0001998"'. 

 The mean is therefore 



A=0'00019965"', 

 or 



A=0-000455 millim. 

 * [Also Phil. Mag. S. 4. vol. xxvi. p. 259.— Ed. Phil. Mag.] 



