Mr. Cavennisn’s, Experiments on Air, 164 
which. phlogifticates the common, air contiguous to ghee a pro- 
duces. fixed - air, »which is immediately abforbed. by the alkali, 
and renders it mild... In the fecond ¢afe, ‘no. inflammable alr is 
produced, the common air is not, phlogifticated; and confe- 
quently the, alkali; remains. cauftic*. This experiment alfo 
proves that metallic calces attract fixed air more ftrongly than 
alkalies attract it; for the ¢alces of zinc are known to contain 
fixed air, and yet alkalies digefted with them remain cauttic ; 3 
and this-accounts for. the flight turbidity of lime-water when 
metals are calcined over it; for as foon as the phlogifton i is 
difengaged from the metal, and before it has abforbed the 
whole quantity of fire requilite to throw it into the form of in- 
flammable air, it meets with the dephlogifticated part of. the 
common air on the furface of the metal, and there, forms fixed 
air, which 1s inftantly abforbed by the calx with which it is in 
eonta&, fo that itis not to be wondered that it does not unite 
to the lime fron which it is diftant. . 
er the Decompofi ition of Nitrous Air sy mixture UNE 
Commoz Air. 
AS foon as Thad heard Mr. Cavenptsn’s paper shade D ” 
‘about trying whether lime would be precipitated from lime- 
water during the procefs, an expetiment I had never made 
before with common air, taking it for granted that it was fo, 
from the repeated experiments of Dr. Prrestiey, and indeed 
of = niet wes had ticated ie aheeee ‘and, in —_ 
* See Mr. ieeclene? seg, soni on zinc. Mem. Par: Ap77s po 7&8. 
+ See a Pr. Ll 4s Ha 2 2Pr, 218. Font. Recherches Phe P7701 Chy. 
Dij. 3240 7 sci ' ‘i 
_ Vor. LXXIV, ee ee ee REE 
