Scientific Intelligence. 419'. 



A'SAq* 4- 2 AAq., or A*S + 6 Aq, leaving out the other in- 

 gredients which are viewed as accidental. 



10. Bavidsonite. — This so-called new species found in the 

 granite of Aberdeen, turns out to be a mere variety of beryl, 

 as is shewn by an examination of its mineralogical characters- 

 **nd chemical composition. — (Poggend.) 



11. Perikline. — Breithaupt gives the name PerikUne to 

 a mineral belonging to the natroniferous felspars, because it 

 possesses a lower specific gravity, and exliibits some difference 

 of magnitude in the angles of its crystals from albite. This 

 mineral, from St Gotthardt, has been analyzed by Thaulow, 

 who finds its composition to be as follows : — Siliceous acid, 

 69.00 : Alumma, 19.43 ; Natron, 11.47 ; Lmie, 0.20= 100.10. 

 This affords the formula, NS3 + 3 AS^ which is that of albite. 

 G. Rose has examined the angle, and finds it somewhat dif- 

 ferent from that of albite, which, however, is nothing more 

 than can be deduced from the ckcumstance that the faces of 

 Perikline are generally more or less streaked an 1 arched or 

 convex. As to the specific gravity, that of albite is = 2.61 to 

 2.63 ; and Perikline from the Tjvol and St Gotthardt = 2.437 

 to 2.457. But when the Perikline was pulverised, its spe- 

 cific gravity was from = 2.637 to 2.647. The specific gravity 

 of pulverised albite was not determined. Hence, Berze.lius 

 considers Perikline and albite as belonging to the same species. 



12. Chloritoide. — This mineral, formerly named chlorite 

 spar, now Chloritoide by G. Rose, was discovered in the marble 

 quarry of Mamorskoi. Bonnsdorf, as stated in G. Rose's 

 Travels to the Altai and the Caspian Sea, found that it is com- 

 posed of siliceous acid 27.48 ; magnesia, 4.29 ; oxide of iron, 

 27.05 ; oxide of manganese, .030 ; alumina, 35.57 ; water, 6.95. 

 Hence, according to Bonnsdorf, its formula = /^ S -f- A'^ S -f 

 ZAfj; which differs from that given by Erdmann. 



13. Scale for the Fiisibiliti/ of Minerals. — Von Kobell has 

 proposed a scale for the fusibility of minerals, as a contribu- 

 tion to the distinctive characters obtained by the blowpipe. 

 He selects the following minerals for his scale, of which the 

 first is the most easily fused, the last the most infusible, 1 . 

 Grey antimony or sulphuret of antimony ; 2. Natrolite ; 3. 

 Almandine ; 4. Actinolite ; 5. Adulai-ia ; G. Diallage. We pi-e- 



