212 Continuation of the Experiments and Gofer vat ions 
tains nearly the whole quantity of phlogifton which iron will 
part with (it being more completely dephlogifticated by this- 
add than by any other means) it follows, that 83,87 cubic 
inches of nitrous air contain at leaf! 5,42 gr. of phlogifton ; 
but it may reafonably be thought that the whole quantity of 
phlogifton which iron will part with is not expelled by the 
vitriolic acid, and that nitrous acid may expel and take up more 
of it. To try whether this was really fo, I calcined a certain 
quantity of green vitriol, until its ferruginous bafts was quite 
inftpid ; 1 then extracted from 64 gr. of this ochre two cubic 
inches of nitrous air, confequently 100 gr. of this ochre would 
give 3,12 cubic inches of nitrous air; and if 83,87 cubic 
inches of nitrous air contain 5,42 of phlogifton, then 3,12 cubic 
inches of this air contain 0,2 of a grain of phlogifton ; confe- 
quently, nitrous acid extrads from 100 gr. of iron two tenths 
of a grain more phlogifton than the vitriolic acid does ; there- 
fore 83,87 cubic inches of nitrous air, containing nearly all the 
phlogifton which iron gives out, contain 5,62 gr. of phlogifton. 
Then 100 cubic inches of nitrous air contain 6,7 gr. of phlo- 
gifton , and ftnce 100 cubic inches of nitrous air weigh 39,9 gr* 
they muft alfo contain 33,2 gr. of nitrous acid. 
Alfo, 1 00 gr. of nitrous air contain 16,792 of phlogifton, and 
83,208 of acid. 
When firft 1 made thefe experiments I imagined, that the ni- 
trous air thus expelled contained all the phlogifton of the metals- 
diflolved in the nitrous acid, as this acid is well known to dephlo- 
gifticate metals as perfedly as pofftble ; but 1 foon obferved, as 
did Dr. priestley and Mr. fontana, that the greater part of 
this is air reforbed and detained in the folution, the acid and calx 
having, according to the beautiful remark of Mr. scheele, a 
greater attradion to phlogifton than either feparately; yet that the 
calculation 
