Fletcher — The Melting- Points of some of the Rarer Minerals. 4:51 



Allanite (Virginia, U.S.A.) : — flows slowly at 1265 and freely at 1280. 

 AUanite (Arendal, Norway): — melts at about 1220, flows slowly at 1255 and 

 readily at 1290. 



SUBSILICATKS. 



Cerite (Koping, Norway) : — becomes round and melts below 1370, but does 



not flow below 1600. The glass is botryoidal and dark brown on thin 



edges. 

 Cerite (Bastnas, Sweden) : — possibly softens at 1230 and melts fairly easily 



at 1350 to a pale yellow glass, which darkens to opacity on heating to 



redness. 



TiTANO-SlLlCATES. 



Titanite (Norway, 1744) : — reddens litmus and yields a white sublimate. 



Softens and melts readily to a rich brown glass at 1250, flowing at 1315 



with iridescence. The fusion shows slight colour-changes on heating. 

 Keilhauite (Kragero, Norway) : — reddens blue litmus paper. Melts, showing 



sublimation, to a pale yellow glass at about 1110 and flows with 



iridescence. The fusion darkens slightly on heating. 



NiOBATES AND TaNTALATES. 



Pyrochlore (Russia) : — yields a white sublimate. The powder, which is 

 difficult to distinguish, shows sublimation in rings at about 1220, 

 partially melts and flows very readily at 1340, and the remaining 

 nucleus at 1425. The fusion shows surface-tension effects and 

 iridescence. 



Fergusonite (Ttterby, Sweden) : — Yields traces of a sublimate, whitens, and 

 turns blue litmus red. Possibly softens at 1300, melts to a dark yellow 

 glass, and flows with difficulty at 1510. 



Fergusonite (Norway) : — Softens at 1330, and flows freely at 1485. 



Coliimbite (Moss, Norway) : — powder turns brown on heating and reddens 

 litmus. Melts at 1310 with iridescence, but does not flow freely. 

 Segregates at 1400 into drops, showing surface-tension effects ; finally 

 disappears. The glass, which is brown on thin edges, tends to crystallize 

 in radiate and sheaf-like needles on cooling. 



ColumUte — (Warwick, New Jersey, 1763) : — powder reddens and yields a 

 vapour affecting blue litmus. Softens without flowing at 1500. 



Columbite (Arendal, Norway) : — melts, but does not flow freely at 1350. 



Wiikite (Impilati, Finland) : — possibly softens at 1250, and slowly melts at 

 about 1385. 



PCIENT. PKOO. K.D.S., VOL. XIII., NO. XXXI. 3 Y 



