190 Influence of Prussie acid upon vegetation. 
dried and heated the light was much more vivid and the colour 
a little reddish. It gave out slight scintillations. The gum 
Arbol-a-brea was more luminous than sugar, and even emitted 
light by friction in water. When these three gums were 
treated with dilute Sulphuric acid, they were phosphorescent 
in the same degree. See the Journal de Pharmacie, April 
1824, p. 193.—-Ibid. , 
31. Minerals produced by heat.—It has been very often ob: 
served, that the analyses of minerals are of comparatively/ 
little value, as long as we are not capable of reproducing by 
composition what had been dissolved. Professor Mistcher- 
lich has accomplished this important object. We have been 
gratified by the sight of beautiful and well defined crystals of 
grayish-white pyroxene, which had been obtained by mixing 
the constituent parts indicated by analysis in the necessary 
proportion, and exposing this mixture to the high degree of 
heat of the porcelain furnaces of Seires. By this means 
Professor Mistcherlich has succeeded in obtaining several spe- 
cies that occur in nature. He has likewise observed among 
the different kinds of slags more than forty species in a crys- 
tallized state, particularly of such minerals as are found in 
primitive rocks, but likewise a good many others which have 
not been hitherto observed. We propose giving in our next 
number a full statement of the further details of these most 
important experiments.—IJbid. 
32. Ammonia disengaged from plants during vegetation.— 
M. Chevalier has determined the very curious fact, that the 
Chenopodium vulvaria spontaneously disengages ammonia in 
a very free state during the act of vegetation; and he has al- 
so found in conjunction with M. Bouliay, that a great number 
of flowers, even among those that have a very agreeable odour 
spontaneously disengage ammonia during vegetatiqn. M. 
hevalier likewise obtained ammonia from the Chenopodium 
vulvaria by distillation. (See the Journal de Pharmacie, 
Feb, 1824, p. 100.)—Jdud. 
33. Influence of prusstc acid upon vegetation —M. C. J. H. 
Becker in his “ dissertatio de Acidi Hydrocyanici vi perniciosa 
in plantas”, which appeared at Jena in 1823, in 4to. has per- 
