^02 Mr. Milner on the Production of 
of nitrous air, and frequently of dephlogifticated nitrous air. 
But I am fatisfied that if the iron tube were fufficiently long, 
fo that a very large portion of it might be heated red-hot, all 
the air received in this manner from any quantity of nitrous 
acid (lowly boiled would be found of that fpecies called phlo- 
gifticated air. 
5, Thefe experiments feem altogether analogous to thofe of 
Dr. Priestley, in which nitrous air, by expofure to iron, is 
converted firft into dephlogifticated nitrous air, and afterwards 
into phlogifticated air. The only difference feems to be, that 
v in my experiments the effect is brought about fuddenly ; 
whereas in the method of expofition to iron much time is re- 
quired. And farther, in my method of operating, it is very 
difficult to conduft the procefs fo as to infure the production of 
that lingular fpecies of air called dephlogifticated nitrous air. 
If the acid boil very quick, the produdt is nearly all nitrous 
vapour and nitrous air. If it boil very (low, and a fufficient 
quantity of the iron tube be well heated, then the decompo- 
iition is almoft complete, and little is received but phlogifti- 
cated air. In both dafes, the progrefs of the converfion of 
nitrous acid to the (late of phlogifticated air feems to be the 
fame. Firft, nitrous air is formed, then dephlogifticated ni- 
trous air, and laftly phlogifticated air. This, I fay, feems to 
me to be the natural order of the converfion, though I do not 
deny, that in the rapid manner of operating with the red-hot 
iron tube fome particles of nitrous acid or vapour may pro- 
bably be injlantly changed into phlogifticated air. And even 
allowing this to be the cafe, the fad may eafily be explained, 
by fuppofing the fucceffive approaches to phlogifticated air to 
be made in too fmall fpaces of time to be obferved ; nor does 
it in the leaft invalidate the general conclufion, that nitrous 
i 
air 
