relating to Air and Water . 307 
gave an addition of fix grains to the piece of iron which had 
been melted in it. But there was always a quantity of fixed 
dir produced in this procefs ; and on the fuppofition that this 
air eonfifts of the union of dephlogifticated and inflammable 
air, it proves that the - dephlogifticated air which enters the 
iron expels more phlogifton than is neceffary to conftitute an 
equal weight of water* fo that water does not contain fo much 
phlogifton as iron ; but the difference is not very conflderable. 
Admitting Mr. Kir-wan’s conclufton, viz. that 100 cubic 
inches of fixed air contain 8,357 grains phlogifton, the .1 3 ounce 
meafure of fixed air, which (in an experiment recited in thefe 
papers) was found in the refiduum of feven ounce meafures of 
dephlogifticated air abforbed by iron, would not have contained 
more than .01 grain of- phlogifton, or about .16 ounce mea- 
fure of inflammable air. Then, as the abforption of 12 
ounce meafures of dephlogifticated air occafioned an addition of 
6 grains to the weight of the iron which had abforbed it, the 
abforption of feven ounce meafures muft have occafioned the 
addition of: 3.5 grains to the iron which had imbibed it. But. 
the fame addition of weight to iron given by Jtedpi (which car- 
ries its own inflammable air along with it) would have expelled 
near 12. ounce, meafures of inflammable air : confequently, , 
about ten ounce, meafures of inflammable air (or the phlogifton, 
requifite to form it) muft, in the/ former experiment, have been 
retained in the iron, in order to compofe the water which was 
now made by the union of the dephlogifticated air imbibed by 
the iron and the phlogifton contained in it : and therefore the 
proportion between the quantity of phlogifton in iron to that 
which is contained in an equal weight of water, may be about 
12 to 10, or more accurately to 10.4. 
Had no fixed air at all been found in the refiduum above- • 
mentioned, it might have been concluded, that water had con- 
R r. 2 .. tained 
