. Intelligence and Miscellaneous, Articles. 1 4,9 



electricity to charge a Leyden jar; and on the other hand, that the 

 charcoal which is contained in vegetables does not give out less elec- 

 tricity than charcoal which burns freely, one may conclude, says 

 M. Pouillet, as my direct experiments tend to prove, that over a suri 

 face of vegetation 100 metres square, more electricity is produced in 

 a day, than is necessary to charge the strongest electrical battery. — 

 Ibid. p. 420. 



ROSE-COLOURED PETROS1LEX FROM SAHLBERGH IN SWEDEN. 



M. Berthier has analysed this substance. Its characters are, that it 

 is compact, homogeneous ; its fracture is very fine-grained, waxy ; its 

 colour is deep flesh red ; it is very translucent, and capable of receiv- 

 ing a fine polish. By the blowpipe it melts into a white enamel; 

 but it is much less fusible than felspar. When it is calcined in a 

 strong white heat, it does not soften, nor does it alter in colour or 

 appearance. When strongly heated in a charcoal crucible in a por- 

 celain furnace, its angles are rounded, it becomes milk-white, and re- 

 sembles chalcedony. It loses only about l-200dth of its weight in 

 this high temperature — a loss which is to be attributed to hygrometric 

 moisture. It yielded by analysis 



Silica*. 79*5 



Alumina 12*2 > 



Soda 06-0 



Magnesia 01*1 



Oxide of iron 00*5 



993 



Ibid. t. xxxvi. p. 22. 



NONTRONITE, A NEW MINERAL. 



This mineral occurs in the arrondissement of Nontron, in the 

 northern part of the department de la Dordogne, which contains a 

 mine of manganese of considerable importance, near the village of 

 Saint Pardoux, in heaps of which this mineral was found. This sub- 

 stance is disseminated throughout the ore in kidney-shaped masses, 

 which are usually very^mall, and are rarely as large as the fist. This 

 mineral is compact, of a straw or canary yellow colour, with a shade 

 of green; its fracture is uneven : it is opake, unctuous to the touch, 

 and very tender ; its consistence is that of clay, and it is easily 

 scratched with the nail ; it takes a fine polish, and assumes a resinous 

 lustre by being rubbed with very soft bodies. It flattens and becomes 

 lumpy under the pestle, and is not reduced to powder ; it has not the 

 argillaceous smell, nor any action upon the magnet. When immersed 

 in Water it immediately disengages numerous bubbles of air ; it be- 

 comes translucent on the edges without softening or losing its form, 

 as clays do ; and if after some hours it is taken from the water and 

 weighed, after being well wiped, it is found to have gained about 

 1-1 0th of its weight of water. When heated in a glass tube it loses 

 water at a low temperature, and becomes of a dirty red colour. When 

 strongly calcined in a crucible, it assumes a similar appearance, and 



its 



