extracted from different Kinds of Waters. 443 
rather more probable, that a quantity of air lefs good is, 
by the action of the vapours and the heat, extricated 
from that impure water, and is mixed with the air that 
comes out of the matrafs; from whence this air is de- 
bafed. 
I muft not omit to mention a new character of equal 
importance with that which diftinguifhes the dephlo- 
gifticated from the common air. This new character has 
been equally unknown, and deferves the attention of 
philofophers, becaufe at the fame time it difcovers a new 
property of the atmofpherical air, which I fhould never 
have fufpected if experience had not offered it to me. - 
I have found, that common air fhaken in water, inftead » 
of being diminifhed is fenfibly increafed in its bulk. The 
increafed fpaee is in proportion to the time the air is fhaken. * 
in water, and it begins to be fenfible even from the begin- 
ning, that is j after a few feconds. This augmentation I 
have fometimes brought to be one twelfth of the bulk of* 
the air, and even more: it muft, however, be confefled, . 
that I met with great variety in the experiments of this 
kind made at different times. After that the bulk of the 
air fhaken in water is increafed to a certain degree, it 
then begins to decreafe continually; and, in proportion 
to this decreafe, the air becomes gradually lefs good. 
When the. experiment is tried in clofe veffels, the dimi- 
nution 
