554 Intelligence and Miscellaneous Articles. 



near Genoa, analysed by Schafhaiitl. I may here remark that I 

 have lately detected vanadium, with chromic iron, and oxide of 

 nickel in a serpentine from Gaspe. 



The true euphotide is then distinct from those diallagic dolerites 

 with which it has been confounded by Delesse, Coquand, and most 

 modern lithologists. I propose soon to send you my results in a 

 detailed form with a sketch of the history of euphotide. — From 

 Silliman's Journal of Science for May 1858. 



ANALYSIS OF THE PEROWSKITE OF SCHELINGEN. BY F. SENECA. 



This mineral was first discovered by Butzengeiger in the granular 

 limestone of Vogtsburg on the Kaiserstuhl, and described by 

 Walchner in 1825. The latter regarded it as titanic acid, viiXh a 

 very small amount of iron, and considered it to be a peculiar species. 

 The same crystals were subsequently described by Quenstedt and 

 Volger as Perowskite. These crystals have been investigated by 

 Seneca in Weltzien's laboratory. 



The ciystals are cubes. Their cleavage is very distinctly parallel 

 to the faces of the cube. The individual crystals are always 

 ao-gregates of smaller cubes, between which delicate films of cal- 

 careous spar are sometimes inserted, as may be easily ascertained 

 by treatment with acids. Spec. grav. = 4-02. Hardness between 

 apatite and felspar. The mineral possesses an iron- black colour and 

 a brilliant, metalHc, glassy lustre ; iridescence is only exhibited 

 during weathering, as in other minerals containing protoxide of 

 iron, the latter becoming converted into hydrated peroxide. Analysis 



gave — 



I. Oxygen. 



TiO^ 58-95 per cent. 23-5 



CaO 35-69 „ 1019 



FeO 6-23 „ 1-38 



II. Oxygen. 



TiO^ 59-30 per cent. 23-61 



CaO 35-94 „ 10-28 



FeO 5-99 „ 1-33 



The amount of oxygen of the base is to that of the acid as 1 : 2, 

 from which results the formula CaO, TiO^, in which the lime is 

 partly replaced by protoxide of iron. According to the formula, 

 Perowskite contains 4109 per cent, of lime and 5891 per cent, of 

 titanic acid. — Liebig's Annalen, civ. p. 371. 



