o40 Dana on Kttrous Gas, 



tion of nitrous acid* The latest chymical publication, Uft^i 

 Dictionary of Chymistry^ 2d edition, Lond. 1823, gives the 

 same theory of its action. To shew the explanation of the 

 eiFect of nitrous gas in eudiometry, as given by chymical 

 authors, I will quote a passage from this dictionary ; and 

 do this because the editor is not less remarkable for sound 

 criticism, than for fulsome flattery of Davy, for cavalier 

 treatment of Thompson, and for total silence respecting the 

 labors of the chymists in this country.* 



"Nitric acid is composed of 100 parts of azote and 200 

 of oxygene, or of 100 oxygene and 200 of nitrous gas 

 = (100 0. + 100 az.) Nitrous vapour, or more properly 

 speaking nitrous acid gas results from the combination of 

 100 oxygene with 300 of nitrous gas. Hence by giving 

 predominance alternately to the oxygene and to the ni- 

 trous gas, we obtain 300 of absorption and nitric acid, or 

 400 of absorption and nitrous acid. The niirous acid is an 

 identical compound, very soluble in water, which it colours 

 at first blue, then green, and lastly orange-yellow. This 

 liquid vpith alkalies forms nitrites. These clear and simple 

 facts constitute the whole theory of the formation of the ni- 

 trous and nitric acids by means of oxygene and nitrous 

 gas, and perlectly explain the differences in the results of 

 those who have operated with them." — Ure's Dic'y. article 

 Eudiometer. 



Now it is perfectly well established th&t nitric acid is a 

 compound of 100 volumes of azote, united to 250 vol- 

 umes of oxygene ; this appears from the experiments both 

 -of Gay Lussac and Davy. (Vide Ure's Dictionary, article 

 acid nitric.) 



If 300 of nitrous gas, united with 100 oxygene. produce a 

 diminution, by absorption, of 400, it is evident that it can- 

 not be by the production of nitrous acid ; because, (since 

 nitrous gas contains one half its volume of oxygene,) the 

 nitrous acid so formed would consist of 150 azote-f-250 

 oxygene; a relative proportion of the two substances which 



*1q this edition of Ure's Dictionary no notice is taken of the New Gal 

 Tanic Instruments of Hare, or of the splendid result^ obtainecl by them in 

 the hands of -rilliman ; nor is justice done to our countrymen respecting 

 the oxy-hydro^ene blowpipe: the Editor of the Dictionary cannot be 

 supposed to be ignorant of these subjects, and a silence respecting them, i« 

 at once uucandid, disrespectful, and disgustinj^. 



