1887] Botany, 475 
in solid and in gaseous species, upon which several chemists 
have in late years insisted. 
The question of heterogeneous and of homogeneous differ- 
entiation or disintegration in gases is also discussed at length 
Miscellaneous.—By subjecting mixtures of zinc salts and 
sulphates of sodium or potassium to a high temperature Alex. 
_ cium, strontium, and barium carbonates crystallized as calcite, 
strontianite, and witherite. The first was accompanied by some 
aragonite. Lead carbonate crystallized as cerussite and hydro- 
cerussite, and cadmium carbonate formed little crystals corre- 
sponding to calcite. The same results were reached by heating 
solutions of the saline salts with ammonium carbonate at 140°. 
Brazilian zoaz possesses an electrical axis which does not 
correspond to any crystallographic axis——E. Cohen * has de- 
scribed pseudomorphs after the concretionary markasite occur- 
ring in the chalk at Riigen, Pomerania. The pseudomorphs 
are composed of a mixture of 9.88 per cent. silica, 11.93 per cent. 
_copiapite, and 78.19 limonite. 
BOTANY:.s 
mut in Oats.——Some recent experiments made at the New 
York Agricultural Experiment Station upon the smut ( Ustilago 
segetum) which affects the panicles of the oat are of such interest 
1 Comptes Rendus, civ., 1887, p. 120; Bull. d. 1. Soc. Chim. d. Paris, xlvii., Feb. 
1887, p. 146. 
2 Ib., ciii., 1886, p. 1083; Bull. d. J. Soc. Chim d. Paris, xlvii., Jan. 1887, p. 81 
3 K. Mack, Pogg. Annalen, 1886, No. 6, p. 153. 
4 Sitzb. d. Naturw. Ver. f. Neuvorpommern u. Rügen, 1886, 
5 Edited by Prof. CHARLES E. Bessey, Lincoln, Nebraska. 
