of some Calamines. 19 
b. One of these crystals, exposed to the flame of the blow- 
pipe, decrepitated and became opaque, and shone with a green 
light, but seemed totally infusible. 
Borax and microcosmic salt dissolved these crystals, without 
any effervescence, producing clear colourless glasses. Carbonate 
of soda had little if any action on them. 
c. According to Mr. Pelletier’s experiments* on the cala- 
mine of Fribourg in Brisgaw, which is undoubtedly of this 
species, its composition is, 
Quartz - - - 0.50 
Calx of zinc - 0.38 
Water - 0.12 
1.00. 
The experiments on the Regbania crystals have had different 
results ; but, though made on much smaller quantities, they 
will perhaps not be found, on repetition, less in conformity with 
nature. 
23.45 grs. heated red hot in a covered crucible, decrepitated 
a little, and became opaque, and lost 1,05 gr. but did not fall 
to powder or grow friable. It was found, that this matter was 
not in the least deprived of its electrical quality by being ignited ; 
and hence, while hot, the fragments of these decrepitated crys- 
tals clung together, and to the crucible. 
d. 22.2 grs. of these decrepitated crystals, = 23.24 grs. of 
the original crystals, in a state of impalpable powder, being 
digested over a spirit-lamp with diluted vitriolic acid, showed no 
effervescence; and, after some time, the mixture became a jelly. 
Exhaled to dryness, and ignited slightly, to expel the superflu- 
ous vitriolic acid, the mass weighed 37.5 grs. 
* Journal de Physique, Tome XX. p. 424. 
D 2 
