sphalerite, which is even more responsive to friction than the native sulphide.*
Mrs. Kunz, wife of the well-known New York mineralogist, possesses, perhaps, the most remarkable of all phosphorescing diamonds. This prodigy diamond will phosphoresce in the dark for some minutes after being exposed to a small pocket electric light, and if rubbed on a piece of cloth a long streak of phosphorescence appears.
Absorption Spectrum of Diamond
On passing a ray of light through a diamond and examining it in a spectroscope, Walter has found in all colourless brilliants of over i carat in weight an absorption band at wave-length 4155 (violet). He
Zinc carbonate . . .100 parts Flower of sulphur . . 3° <
Manganese sulphate . . \ per cent.
Mix with distilled water and dry at a gentle heat. Put in luted crucible and keep at a bright red heat for from two to three hours. 101
