of Several Minerals. 73 



36. Axotomous Lead-baryte, (sulphato-tri-carbonate of lead,) the 

 acute crystals commonly called rhombohedrons, of a dark yellow- 

 ish-grey colour, and translucent, from Leadhills, 6.266 



37. Axotomous Lead-baryte, the six-sided laminae, of a pale 

 yellowish white colour, semitransparent, from Leadhills, 6.364 



During the late stay of Professors Mitscherlich and Rose 

 in Edinburgh, I have had occasion to show them those spe- 

 cimens from which I had derived the hemi-prismatic form of 

 the species. They have been perfectly convinced of the ac- 

 curacy of my observations, called in question by Mr. Brooke, 

 (Edin. Phil. Journ. No. XXI. p. 157.) They have also ob- 

 served the double system of coloured rings exhibited by the 

 mineral in polarised light, in a plane passing through the 

 short diagonal of the oblique prism of 59° 40', and the nume- 

 rous regular compositions, not only deducible from experi- 

 ments in polarised light, but also from the lines upon the 

 face of P — oo, and some that occur in other directions, of 

 which I shall give a description, among the regular composi- 

 tions of hemi-prismatic substances. 



38. White antimony, transparent crystals, about 1'" in diame- 

 ter, yellowish- white, from Braunsdorf, Saxony, 5.566 



Order III. Kerate. 



1. Horn-ore, a very pure, greyish- white, translucent variety, 

 compounded of granular individuals, from Peru, 5.552 



Order IV. Malachite. 



1 . Copper-green, massive, fracture conchoidal j colour, dark 

 verdigris green, translucent, from Siberia, 2.031 



2. Copper-green, thin botryoidal coats upon compact brown 

 iron-ore, pale green, faintly translucent, Bannat, 2.206 



3. Prismatic Lirocone-malachite, (lenticular copper,) sky-blue 

 crystals, from Cornwall, 2.926 



4. Prismatic Azure-malachite, (blue carbonate of copper,) frag- 

 ments of very pure crystals, from Chessy, 3.831 



5. Malachite, a cleavable dark-green variety, from Chessy, 4.008 



6. Malachite, a fibrous dark-green variety, from Siberia, 3.802 



7. Malachite, perfectly compact, of a pale green colour, opaque, 



from Schwatz, Tyrol, 3.670 



8. Prismatic Habroneme-malachile, (phosphate of copper,) 

 dark-green crystalline coat, from Rheinbreitbach on the Rhine, 4.206 



*!). The Radiated acicular olivcnite of Jameson, oblique pris- 

 matic arseniate of Phillips, globular shapes of a dark blue colour, 

 a little greenish, translucent, 4.192 



