42 Mr. Balmain's New Process for preparing Oxygen, 



same equations ; and denote, as before, the denominators by 

 Dj and D 2 respectively : then 



v _ * (ft + 7) *i ** v _ /3(* + g)y t yn 



> . . (10.) 



Substitute these in the expression X 2 Y l — Xj Y 2 , and 

 we have X^-X^ 



_ (« + 8)Q3 + y)jf l y 1 .jr 8 y a _ Q8 + y) (« + 8) g 8 y 8 .gi.y» 

 DiD 2 D.D, 



= 0, 

 which is again the ordinary criterion of G H passing through 

 the origin, O. 



Royal Military Academy, 

 May Uh, 1842. 



IX. New Process for Preparing Oxygen By W. H. Balmain, 



Esq. 



To the Editors of the Philosophical Magazine and Journal. 

 Gentlemen, 



/"^XYGEN being much in request for the oxyhydrogen 

 ^•f blow-pipe, and indeed for purposes of illumination, it 

 is important to have an expeditious and cheap process for 

 preparing it. Moreover, in the present day, when practical 

 chemistry is becoming so popular, it will, independently of 

 all matter of expense, be no insignificant acquisition to the 

 lecturer and juvenile experimentalist to have a ready method 

 of preparing the principal supporter of combustion. It has 

 occurred to me that it may be prepared from bichromate of 

 potash by the action of sulphuric acid; and as the process has 

 upon trial proved successful, I beg leave to suggest it to those 

 whom it may concern through the medium of your Journal. 



A mixture of three parts of bichromate of potash and four 

 parts of common sulphuric acid contained in a capacious re- 

 tort, will, on the application of a moderate heat, yield pure 

 oxygen with a rapidity entirely at the command of the ope- 

 rator. 



K Chr 2 . S 4 H 4 nrnAl „ a K SandChr, 3 + S, 



47-5+104= 151-5 ana 160+36=196 P roauce 47'5+40+ 56 +24+120 



= 287'5 and 36 and 24' 



