[ 28: J 
meafure, as is exprefied in the plate 
by BB in Fig. I. Then I obferve 
with what number of the fcale the 
firft divifion of the glafs tube above 
the column of water coincides, 
which fhews me at once how many 
fub-divifions. are remaining from 
the two meafures of airs, or from 
the 200 fubdivifions let up in the 
. tube, and thus indicates the degree 
of SRREOERD of common 55) or in- 
coal to common aS ‘bein: 
of an inferior quality. But this 
-method will not do in examining 
dephlogifticated air, as this air re- 
quires more nitrous air to bring it 
to a full faturation. By this fimple 
and eafy method the whole opera- 
tion is performed in three or four 
minutes ; and its accuracy is-fuch, 
that iy | in ten trials, made 
with 
