Natural History. -—Miner alogy^ 'IS’J 
small quantity. Ammonia, caustic potassa, and bi-carbonate of 
potassa, with phosphate of soda, gave indications of magnesia. 
Nitro-muriate of platinum gave a slight intimation of potassa. 
Per-muriate of ammonia gave slight traces of alumina. No 
whatever was obtained. From this examination by rea- 
gents, therefore, it may be assumed that the chemical conslitii’ 
ents of the liquid in question consist of 
Sulphate of Lime, Muriate of Soda, 
of Alumina, of Magnesia, 
of Iron, — - of Potassa. 
■ m. NATURAL IIISFOllY. 
MINERALOGY. 
16. Sulphato4ri-carbonate q/^ Lead.— A very fine speciniGit. 
of carbonate of lead was recently brought from Leadhills, by 
Alexander Irving, Esq., who found it by analysis to be a sul- 
phato-carbonate. Upon examining its crystals, I find it to be 
the Sulphato-tri-carbcmate of Mr Brooke The crystals, which 
are of considerable size, are acute rhomboids, with cleavages 
perpendicular to the axis of the rhomb. They are of a bright 
sap-green colour. Upon examining their optical structure, I 
find that they have two axes of double refraction, the principal 
one of which is coincident with the axis of the rhomb. The 
sulphato-tri-carbonate, therefore, cannot have the acute Rhom- 
boid for its primitive form, but must belong to the Prismatic 
system of Mohs. — D. B. 
17. Calc-sinter determined to he true Calcareous-spar.— 
Reverend Dr Fleming of Flisk transmitted to me lately two 
specimens of this substance, with the following remark : 
1. Lamellar Calc-sinter from MacalisteFs Cave in Sky. I pro- 
cured these crystals in shallow pools in the cave filled with the 
calcareous water. The indications of crystallization are dis- 
tinct, but the crystals seem to be but in progress. The sum- 
mits of the crystals of the smallest piece are smooth and flat, 
and indicate the prisms below to be five-sided, and sometimes 
See this Journal, Vol. III. p, 119 , 
