37<> Mr. Macie’s Account of 
(G) A quantity of this Tabaftieer which weighed 75.7 gr. 
in air, weighed only 41 . 1 gr. in diftillad water whofe tempe- 
rature was 52.5 F. which makes its fpecific gravity to be very 
nearly —2.188. 
Mr. Cavendish, having tried this fame parcel when becorrle 
again quite dry, found its fpecific gravity to be = 2. 169. 
Treated with water . 
§ IL (A) Th is Tabaftieer, put into water, emitted a number 
of bubbles of air; the white opaque bits became tranfparent 
in a fmall degree only, but the bluifh ones nearly as much 
fo as glafs. In this ftate the different colour produced by 
reflected and by tranfmitted light was very fenfible. 
(B) Four bits of this fubftance, weighing together, while 
dry and opaque, 4.1 gr., were put into diftilled water, and let 
become tranfparent ; being .then taken out, and the unab- 
forbed water haftily wiped from their furface, they were again 
weighed, and were found to equal 8.2 gr. 
In the experiment § I. (G), 75.7 gr. of this fubftance ab- 
fprbed 69,5 gr. of diftilled water. 
(C) Four bits of Tabaftieer, weighing together 3.2 gr. were 
boiled for 30' in half an ounce of diftilled water in a Florence 
fiafk, which had been previoufly rinced with fome of the fame 
fluid. This water, when become cold, did not ftiew any 
change on the admixture of vitriolic acid, of acid of fugar, 
nor of folutions of nitre of filver, or of cryftals of foda ; yet, 
on its evaporation, it left a white film on the glafs, which 
could not be got off by wafhing in cold water, nor by hot 
marine 
