produced in the Prismatic Spectrum. 87 



duced. Chlorous acid, in very small quantity, is capable of 

 tinging a very large bulk of water of a bright yellow colour. 

 As the gas had so marked an effect on the spectrum, I was 

 induced to try this solution, but failed entirely in discovering 

 lines ; the liquid arrested the whole of the more refrangible 

 rays entirely, no light passing beyond the midspace between 

 E and F. 



I now prepared some pure peroxide of chlorine (Clg Og), 

 freeing it from chlorine and chlorous acid, by which it is al- 

 ways accompanied, by passing the gas through tubes sur- 

 rounded with a mixture of ice and salt; the peroxide alone 

 condenses at this temperature, and the deep red liquid thus 

 obtained was allowed to fall into a tube and evaporate; the 

 same series of lines were produced. In this gas, which has a 

 specific gravity of 2*325, 1 vol. of chlorine and 2 vols, of oxy- 

 gen are condensed into the space of 2 vols. 



Euchlori?ie was next tried ; the gas was disengaged from a 

 mixture of hydrochloric acid and chlorate of potash, conden- 

 sing the compound as before by a freezing mixture : to this 

 compound Millon assigns the curious formula of CI3O13; here 

 too 1 found the same series of lines. Millon's theory of the 

 composition of these bodies is, that the peroxide of chlorine is 

 a compound ai chloric and chlorous acids in single equivalents, 

 as it is immediately resolved into these two acids by the action 

 of alkalies; and lie considers the euchlorine, or chloro-chloric 

 acid, as he proposes to call it, a compound of 1 eq. CI Og with 

 2 CIO5, the action of acids, immediately resolving it into those 

 acids in the proportions just mentioned. Certainly the oc- 

 currence of similar lines in all three, although the condensa- 

 tion varies, does not militate against this view, but increases 

 its probability. 



Millon's new compound, chloro-perchloric acid, which re- 

 sults from the action of solar light on chlorous acid, I have 

 not hitherto obtained in a state of sufficient purity to pronounce 

 upon. 



It is remarkable that the hypochlorous acid (Clg Og), though 

 of a bright greenish-yellow, furnishes no such lines; the den- 

 sity of this gas is 5'881, 2 vols, of chlorine and 1 of oxygen 

 being condensed into 1. It is an interesting fact, that the 

 colourless protoxide of nitrogen^ in which 2 vols, of nitrogen 

 and 1 vol. of oxygen are condensed into 2, having a specific 

 gravity of 1 •524', has also no sensible effect upon the spec- 

 trum. 



In the series of oxides of nitrogen, the hinoxide^ NOg, in 

 which 1 vol. of nitrogen is united with 1 vol. of oxygen with- 

 out condensation, also a colourless gas, has no effect on the 



