Imperial Society of Natural History of Moscow. 73 



of the season they procured but few plants or insects, but 

 they were more fortunate in their mineralogical pursuits. 

 Petrifactions of all. kinds, several mineral springs rich in 

 iron and carbonic acid, a good clay for earthenware, La- 

 brador stone, garnets in granite and in gneus, granatite 

 in gneus, and a new earthy substance, were procured by 

 them. This new substance is of a very fine lavender blue, 

 and is found in veins several lines thick between layers of 

 cimolitc, which in some places forms the transition to a 

 true mountain cork. Sometimes it is found on round 

 masses of flint, sometimes fossil shells are found in it, and 

 pectinitcs which are wholly black and changed into flint. 

 This substance contains, according to the analyses of 

 Messrs. Helm and Muller, lime, alumine, and phosphoric 

 acid. It forms, therefore, a new species adjoining the 

 Apatite, and it has been designated by the name of Katof- 

 kite, from the place where M. Fischer resides. 



Mr. Davy's experiments. — M. Jacquin in a letter to 

 M. Fischer informs him, that in concert with his friends 

 the director Schreibers, colonel Tihursky, and M. JBremser, 

 he repeated the recent experiments of Mr. Davy with suc- 

 cess. They generally made use of a battery with vertical 

 piles composed of 1300 pairs of disks, which were generally 

 three inches in diameter, and formed together 70 square 

 feet of surface in contact: — the experiment succeeded how- 

 ever with 300 pairs of disks, and it was even perceptible 

 with 70 pairs. One of the processes adopted by the above 

 gentlemen seems to be somewhat novel : they placed in 

 a wine glass a small piece of alkali moistened in the air, on 

 a small plate of platina which communicates with the hy- 

 drogen pole, and which was entirely covered with rectified 

 petroleum. Finally, they placed on the alkali a thin plate 

 of platina, <md pressed it with a metallic rod communicating 

 with the oxygen pole. The effects being remarked, bub- 

 bles of air were extricated as in the first experiment; 

 sometimes there were trifling detonations ; and sometime 

 afterwards they found the whole of the inferior surface of 

 the alkali strewed with small scales having a metallic ap- 

 pearance like those which are seen floating in the petroleum. 

 This preparation is very beautiful, particularly when placed 

 in the microscope. It is not combined easilv wiih mer- 

 cury ; for a globule adhering to the point of the brass wire, 

 when plunged in mercury, was not detached, and after- 

 wards detonated in water as before. 



In the experiment last described, the place of the platina 

 may be supplied by a flat piece of charcoal. The diamond 



and 



