;88 Dr. W. A. Miller on some Cases of Lmes 



spectrum. No oxide corresponding to this in the chlorine 

 series is as yet known. 



Hyponitrous acid I have not isolated in sufficient purity to 

 furnish trustworthy results. 



Fig. 6 represents the grouping of these lines as seen in day- 

 light transmitted through the vapours of j)erchloride of man- 

 ganese, which is readily prepared by adding a few crystals of 

 permanganate of potash to oil of vitriol in a test-tube, and 

 dropping in a fragment of fused chloride of sodium, a green 

 vapour (MngCly) is immediately liberated, which is however 

 quickly decomposed by the moisture of the air. It will be 

 remarked, that in this vapour, the colour of which is green, the 

 lines are most abundant in the green part of the spectrum, the 

 green tint of the gas being due principally to the mixture of 

 the blue and yellow rays. 



The perjluoride of manganese, which corresponds in compo- 

 sition to the perchloride, does not yield any lines that I could 

 perceive, but the moment a fragment of common salt is dropped 

 into the mixture from which the fluoride is being disengaged, 

 the lines of the perchloride make their appearance. Both the 

 perchloride and perfluoride are decomposed by water, and on 

 dropping in a little of this fluid into the tube of perchloride, 

 all the lines instantaneously disappear. The purple vapour of 

 the permanganic acid, in which the number of equivalents of 

 oxygen corresponds to that of chlorine and fluorine in these 

 compounds, is equally inactive with the fluoride. 



I have examined very many other substances which yield 

 vapours of different colours, but have not succeeded in finding 

 any which give distinct lines besides those above mentioned, 

 with the telescope which I employed. It was not, however, 

 an instrument of very high power. 



Simple bodies : — 



Chlorine. — Greenish-yellow colour; specific gravity 2*47. 

 This is the more remarkable, as bromine and iodine both give 

 them. 



Sulphur. — Yellow ; specific gravity 6'654!. 



Selc?iium. — Yellow. 



Compounds : — 



Selenious acid. — Yellow (Se02). 



Hypochlorous acid. — Yellow; specific gravity 2*993 (CJgOJ. 



Oxy chloride of chromium. — (Cr CI Oc,); red vapours*. 



Oxychloride of tungsten. — (WCIO^) ; red vapours. 



Ter chloride of tungsten. — (WClg); red. 



* i'rof. Miller informs me, that by means of an instrument of superior 

 quality, he has succeeded in satisfying himself that lines are produced by 

 this vapour. 



