residuum, containing oxygenous gas ^ if nwrc> 

 .then some residuary, nitrqus gas wiJl be founds 



These facts clearly point ^ut the theqry of 

 ^h^ process : tjie elen^erits^, of Qxygea^.pay 

 combine with ^certain portion of, r^itrous. gas, 

 or with twice that portion,, but with no inter- 

 fnediate quantity. In the former case ?z?7rzc 

 acid is the result ; in the., latter nitrqii$ acid ; 

 but as both these may rb^^r formed aVthes^mp 

 time, ope part of the.oxjgen going tq. (?w^ of 

 nitrous gas, and anofher to ,tivo^ the, quantity 

 of nitrous gas absorbed " should be vai:iable j 

 from 36 to 72 per cent, for common pir, This 

 is. the principal cause of ,'fliat diversity which 

 has so much appeared in the results of chemists 

 pnthis subject. In fact,^ all the gradation, in 

 c^UcLntity . of nitrous gas from 36 to -72 . may 

 actually be observed with atmospheric air of 

 the &ame purity j the wider the tube^ or vessel 

 the mi^^ture is made in,. tne' quicker the com-] 

 bmation is enected, and the rnore exposed to 

 waterj the greater is the quantity or mtrpiis 

 acid and the less .of nitric that Is formed, , ^ . 



To .use nitrous gas for the purpose of eudip- 

 metry thereWe, we must attempt to form nitric 

 acid 0% uitTfous wl^olly,ai>d without a ijpixture 

 of the other. Of these the former appears from 

 my experiments to be rnost easily and most ac- 

 curately effected. In order to this a narrow 



