444 Scientific Intelligence. — Mineralogy. 



solution both silex and carbonate of lime. We find both 

 these earths in warm springs that issue from the volcanic 

 rocks ; e. g. water charged with carbonate of lime is now issu- 

 ing from the trap-rocks of Clermont, in Auvergne, and de- 

 posits of siliceous stone are daily accumulating around the 

 orifice of the geyser, in Iceland. Recent discoveries of marine 

 infusoria in the sea-water, co-existing with microscopic mol- 

 luscs, lead us to infer from analogy the high probability that 

 similar animalcules were not less abundant in the ancient seas. 

 We may therefore expect to discover fossil infusoria by the 

 application of the microscope to thin slices of all siliceous and 

 calcareous sedimentary rocks, that contain any other kind of 

 marine or fresh-water remains. In this extension of the ap- 

 plication of the microscope from the living to the fossil infu- 

 soria and foraminifers, we are commencing a new and im- 

 portant era in palaeontology, which will demonstrate a won- 

 derful and very extensive, but by no means exclusive, agency 

 of animalcules in the formation of limestone. In the case of 

 crystalline marbles, it is probable that if any organic remains 

 were ever contained in them, they have been obliterated by 

 heat. 



2. Kilbrickenite. — Kilbrickenite, as Dr Apjohn proposed to 

 call a new mineral from Kilbricken lead-mine, county of Clare, 

 is obviously what Berzelius denominates a sulphur-salt, i. e. a 

 combination of an electro-negative with an electro-positive 

 sulphuret. But there are several other ores known to mine- 

 ralogists, composed of the same proximate constituents, or 

 including sulphuret of lead in association with the sulphuret of 

 antimony. The subjoined list comprehends those which have 

 been analyzed and described : — 



Zinkcnite, . . S, Pb + S : , Sb. 



Plagionite, . 4 (S, Pb) + 3 (S , Sb.) 



Jamesonitc, . . [5 (S, Pb) + Ss, Pb.] + 4 (S 3 , Sb) 1 



Feather ore of lead, 2 (S, Pb) + S h Sb. 



Eoulangerite, . . 3 (S, Pb) + Sj, Sb. 



A mere inspection of the formulae is sufficient to shew that 

 each mineral in this list is distinct in composition from that 

 whose analysis has been given above. There is, however, an 

 ore possessing a constitution perfectly analogous to the Irish 

 mineral, namely, the Sprodglaserz of Mohs and Werner, or 



