Kunzite, 1/- per gramme. Selected, clear, 2/-

Sparteite (see Nature, 31 3/04, fol. 523), 2/- and upwards.

Chlorophane, 2/- and upwards. Barium Platino Cyanide in large Crystals in course of manufacture. (Orders Booked).

Zinc Sulphide. Phosphorescing a beautiful Green, 2/6 per tube.

Zinc Sulphide. Phosphorescing a beautiful Yellow, 2/6 per tube.

Calcium Sulphide Phosphorescing a beautiful Violet, 1/- per tube.

Radio-active Residue from which Radium is made; very scarce, 2/- tube.

Polonium Sulphide, in tubes of one gramme, 21/-

Polonium on Bismuth Rod or Disc, 25/-

Polonium on Copper Rod or Disc, 25/-