366 RELATIVE ATTRACTIONS OF 
temperature had during the greater part of that 
interval been 48° (the maximum temperature of 
the previous week’s interval, ) I conclude that the 
acid the subject of each experiment, had become . 
concentrated to as high a degree as it was capable 
of being, under the circumstances, and by no 
higher a temperature than 48°. 
Then, 76.1—52.6=23.5 grains of water di- 
luting the 200 grains of concentrated acid (sp. 
gr. 1.8428,) at the conclusion of the experiment 
under the exhausted receiver. And, 75.5—23.8 
=51.7 grains of water diluting the 200 grains of 
concentrated acid, at the conclusion of the experi- 
ment under the unexhausted receiver.—The acid 
in the dish under the exhausted receiver, was, 
therefore, so far concentrated as to contain 70.69 
anhydrous acid per cent.; and that in the dish 
under the unexhausted receiver, 62.77 per cent. 
It appears, from the results of these experi- 
ments, that weaker acid is required to render 
atmospheric air, at its usual pressure, anhy- 
drous, than what is required to render a vacuum, 
of the same temperature, anhydrous ; or, that the 
evaporating force of air, exerted upon diluted 
sulphuric acid, is less than that of a vacuum 
