Foreign Notices in Mineratogy, &c. 29 
ticed by Count Bournon, and one by Mr. Sowerby. I 
shall designate them by the names of 
Sulphato-carbonate of lead. 
Sulphato-tri-carbonate of tead. 
Cupreous sulphato-carbonate of lead. 
Count Bournon has described the first merely as a variety 
of carbonate of lead. The second he calls rhomboidal 
carbonate, and describes it as dissolving more readily in ni- 
tric acid, and with greater effervescence than common car- 
bonate. Its primary form he supposes to be a rhomboid of 
60° and 120°. The third species has been called by Mr. 
Sowerby, in his British Mineralogy, Green Carbonate of 
Copper. 
The difference between the external characters of this 
third species and green carbonate of copper, and between 
that of the two first species and any carbonate of lead I had 
seen, induced me to dissolve some of the rhomboidal crys- 
tals in nitric acid. The effervescence was considerable, 
as described by Count Bournou ; but I was surprised to 
observe, after the effervescence had ceased, a white insolu- 
ble residuum, which, on examination, proved to be sul- 
phate of lead. 
In consequence of the observation of this fact, and of 
the: association generally on the same specimen of the three 
varieties, or some two of them, I have examined them all, 
and I believe the following results will be found correct: 
The sulphato- conbonate consists of 1 atom sulphate fiead 
1 ‘* carbonate ; fe ge 
Diener cele while dissolving in nitric acid, scarcely 
perceptible. 
Specific gravity, 6.8 to 7. 
Hardness nearly as sulphate-tri-carbonate. 
Colour whitish, bluish, and greenish-grey, sometimes 
approaching to apple green. The crystals Ihave seen are 
seldom distinct, always minute, and aggregated together 
lengthwise, presenting a character approaching to fibrous. 
From the measurements taken by the reflective goniom- 
eter on two cleavages; from the character of some of its 
secondary planes; and from the observation of its cleaving 
more readily in one particular direction than in any other, 
