Scientific Intelligence, — Mineralogy. 195 



= 98.16. — Arsenical Pyrites from Sladming. Sulphur, 5.20. 

 Arsenic, 60.41. Iron, J 3.49. Nickel, 13.37. Cobalt, 5.10 

 = 97.57. 



1 7. Harmotomejrom Strontian. — The figures of the crystals 

 of harmotome from Strontian, referred to in Mr ConnelPs paper 

 on the composition of that mineral, in the Number of this Journal 

 for July 183.^^ having been accidentally omitted, they are given 

 in the present Number, Plate II. Fig. 7. represents the ordi- 

 nary crystal of the mineral from the above locality ; Fig, 5. the 

 modification of Fig. 7., which was the subject of analysis ; and 

 Fig. 6. the intermediate form. The three forms are particularly 

 described in the paper referred to. 



18. Fertilizing Property of Gypsum or Sulphate of Lime. — In 

 order to determine the manner in which gypsum contributes 

 to vegetable growth, M. Peschier of Geneva, performed several 

 comparative experiments. Two theories have been suggested 

 by chemists, — one, that the gypsum acts simply as a stimulus 

 to the organs of the plant, — the other, that it gives up to the 

 plant its water of crystallization. M. Peschier filled two vessels 

 with siliceous sand, slightly moistened, and sowed in each of 

 them a few seeds of water-cresses, and watered one of them 

 with pure water, and the other with a solution of the sulphate 

 of lime. The plants, when a few inches high, were burned, 

 and equal quantities of their ashes were analyzed. In those 

 watered with the solution of sulphate of lime, there was found 

 a much more considerable quantity of sulphate of potash than 

 in the other. In a second experiment, he found that the pro- 

 portion of sulphate of potash was increased when the plants wa» 

 tered with the solution of sulphate of lime were subjected to 

 the gypsum of a galvanic current. M. Peschier thence infers that 

 the plaster undergoes a decomposition by the act of vegetation, 

 and he thinks he has observed that crude gypsum is more effi- 

 cacious than that which has been calcined. — Rev. Encyc. Nov, 

 1831. 



BOTANY. 



19. Secretion of Water by certain Plants. — Professor L. C. 

 Treviranus of Breslau has lately given his attention to the sub- 



n2 



