190 Scientific Intelligence — Mineralogy. 



From these analyses M. Dolesse deduces the following formula : — 

 Si 0^ 3 Ti 0-+ Si 0"% 3 (CaO, MnO), which corresponds ex- 

 actly with the formula given by Henry Rose for sphene. Professor 

 Marignac also analysed the Greenovite, and obtained nearly the same 

 results, with the exception, that he found a larger quantity of lime, 

 and a smaller proportion of the oxide of manganese ; but, as these 

 bases are isomorphous, their relative proportions may vary in differ- 

 ent specimens. Professor Marignac states that, along with JI. Des- 

 cloizeaux, he obtained a considerable number of specimens of Green- 

 ovite at Saint- iMarcel, near Aoste, and that the cxaniination of its 

 crystals has convinced him that all the forms can be referred to 

 those of sphene. This conviction has been confirmed by the dis- 

 covery of a crystal of sphene from St Gothard, which .accidentally 

 presented cleavage faces parallel to the faces of the ordinary prism 

 of the Greenovite. M.M. Dufrenoy and Doscloizeaux are about to 

 publish a description of the crystallogrnphic forms of Greenovite. 



15. Magnesian Apatite, a New Mineral described by Hermann. 

 — It occurs near Kusiusk, in the Schischimian Mountains, in a 

 vein traversing chlorite slate, and is associated with ci-ystallized 

 ■chlorite (Leuchtenbergite), apatite, chlorospinel, and magnetic iron 

 ore. It is always crystallized in regular six-sided prisms, which are 

 from a few lines to several inches in length, but are of comparatively 

 small diameter. The crystals are arranged in stellular or irregular 

 groups. There is no trace of cleavage planes; but still the crystals 

 are fissured in a direction perpendicular to the principal axis. Ex- 

 ternally the mineral is generally weathered, and is dull, earthy- 

 looking, and yellowish ; on the fresh splintery fracture, however, it 

 is milk-white, and translucent on the edges. The hardness = that 

 of apatite. The specific gravity from 2-70 to 2-75. Its characters 

 before the blowpipe arc like those of apatite. The following is the 

 analysis : — 



Lime, 37'50 



Magnesia, 7"74: 



Phosphoric Acid, . . . 39-02 



Sulphuric Acid, .... 2-10 



Chlorine 0'91 



Oxide of Iron, .... 1-00 



Fluorine and loss, . . . 2'23 



Insoluble, 9-50 



100-00 



As the magnesian apatite is very similar in colour, structure, &c. 

 to the phosphorite of Estremadura, the latter was examined for 

 magnesia, but no trace of it could be found. — {Erdm, und March. 

 Journ. xxxi. 101 ; and Leonhard und Bronn^s Jahrbuch, 1844, 

 Heft 6, p. 720.) 



16. Identity of Mellilite and Humholdtilite. — The analyses of 

 Damour have proved that these two substances belong to one and 



