[ 222 ] 
It hath been /hewn by Moiif. Mariotte, th.it air is 
imbibed, in confiderable quantities, by common wa- 
ter, and may again be feparated from it, either by 
heat, OF elfe by cold, as in congelation ; or by re- 
moving from it the pre/Ture of the atmol'phere, as in 
the exhaufted receiver of an air-pump. And Dodfor 
Shaw relates that, without any of thefe aids, air 
feparates fpontaneoully from the mineral water of 
Scarborough, and that, in a few minutes,, he col- 
leded into bladders large quantities of air, from bottles 
of that water, after the manner attempted in the fore- 
going experiments j he alfo relates, that the airfeemed 
to arife from the water with fome degree of force, 
and continued long in an elaflic date. The fame 
experiment was fince tried, by Dodor Home, on the 
Chalybeate waters of Dunfe in Scotland •f- j who af- 
fures us, that he thus colleded confiderable quantities 
of true permanent air from thofe waters j which, with 
Dodor Shaw, he conjedures in no refped to differ 
from the common air of the atmofphere. And as I 
had no doubt of the accuracy and fidelity of thofe 
gentlemen in their experiments j and had entertained 
an opinion that the mod fpirituous acidulae contained 
the mod air, which, it was reafonable to fuppofe, 
might be feparated from them in the fame manner 
that it was feparable from thofe that were lefs fpiritu- 
ous ; I therefore was greatly difappointed in my ex- 
pedations, when I could not obtain any air from the 
PoLihon water after the manner above related. I did 
* See his Inquiry into the Contents, Virtues, and Ufes of 
the Scarborough Spavv waters. Part II. Se£t. IV, 
t ElTay on the Contents and Virtues of Dunfe Spaw, Edin* 
burgh, 1751. page 99, &c. 
not. 
