) Dr. WitneRine’s Experiments and Objervations. 
f j eRe RS eye uy } 

- = ' m8 ~ rr. ¢ 
r e my me : das 5 ? Pee ie 1 TR. PE wie a Aint 
MALE Stine de Te ba ag BAG ' Pe ay ke. as Fe EAE RD A st LD bat 
CONG .L.05S Ft 0. WS 
HER appears, that 100 parts of this fpar contain — 
‘ Bias PHT Lf 
Terra ponderofa. pura - 78,6 e "is 
Marmor metallicum ms ics pee, a4 
J . <- mh * i \ x f ; “s p ' } } £7 ‘ 7 ‘, 
Fixed air - = i) HO 
é WEE ; Se i > 
roo! siser bsp 
ee ee 
OBSPRVATIONS. 
rft,, The quantity ae rail fixed: alkaly neceflary to faeurate. 
an acid, prev rouflyuniced to the terra ponderofa, ‘contains mere 
fixed air than i neceflar y to faturate that quay of terra pon- 
derofa D- | “r 
2dly, “The « terra ponderoia, when precipitated from an: said 
by means of a mild fixed alkaly (O."T: 2); readily burns ‘to! 
lime; and this. lime-water proves ree nice teft of the pre= 
fence of vitriolic acid. E.-2. 3. 
3dly, It is very remarkable, ‘tha tt the terra ponderofa: far, 
iI 
_ 
its native ftate, will not burn to lime. In the lower degrees 
of heat it fuffers no change, as- was before obferved,. befides. 
the lofs of its traniparency. When urged with a ftronger fire, 
it Melts and unites to: the crucible,. but does not. become cauttic. 
Y buried’ it in charcoal-duft in a covered’ crucible, and then — 
<pofed’ it toa pretty ftrong heat; but it did net part with its 
air, he 
May we not conjecture, theny that as cauftic lime cannot 
anite to fixed air without the intervention of moiftcre, and as 
this. Bi {cems to contain no- water im its compoiition, that it 
fo’ ig 

