[ 228 ] 
the other principles of the Pouhon water, and Is kept 
from contadl of common air, and of fuch other bo- 
dies as are found to decompofe this water, it remains 
in a quiet difTolved flate, intimately mixed with the 
other principles of which this water is»compofed, 
and fo clofely joined to them, that it is not readily 
feparated from them by a lefs heat than that of loo 
degrees of Fahrenheit’s thermometer ; which heat it 
endures for feveral hours, before it is entirely detached 
from its union with them. It alfo appears, from the 
above experiment, that in proportion as this mineral 
air is feparated by heat, in the fame proportion the 
more grofs earthy parts of the water feem alfo to fe- 
parate from it ; and that as the mineral air is thus 
entirely expelled, the water is then wholly decom- 
pofed, its metalline and earthy particles having fub- 
fided, its more volatile and elaftic principles being 
exhaled, and nothing remaining in the water, fave 
only the fmall portion of alkaline and neutral fait, 
which is found diffolved therein. 
It may here be noted, that the numerous analyfes 
of thefe waters, which have been attempted in re- 
torts and receivers where the water was expofed 
with a large furface to the common air, the eladic 
fubftance feems to have been extraded from the wa- 
ter more readily, and with lefs heat than in the pre- 
ceding experiment ; and pellicles have lometimes 
been obferved -f* on the water in the retort, as on the 
fame water expofed to the open air ; the caufes o-f 
which pha^nomena will be explained hereafter. 
* See De Prefieux, Chrouet, Le Dran, Limbourg, Lucas, 5ic. 
t Sec De Preffeux. 
Experiment 
