516 The American Naturalist. 



[.lu... 



of the joint cracks. P and oP are the only faces observed on the 



anatase. Crystalline masses of ilvaite are reported by HoiFman 1 



from a twenty-foot vein near the head of Barclay Sound, Vancouver 

 Island, British Columbia. Its hardness is 5.5, density 3.85 and com- 

 position : 



29.81 .16 



Celestite from Scharfenberg, near Meissen, Saxony, according to 

 Stuber 2 occurs in druses of little blue crystals whose axial ratio is 

 .7807 : 1 : 1.2834, and whose habit is determined by the planes P^, 

 oP and aPacT. Another druse is made up of brown or wine-yellow 

 crystals whose habit differs from that of the blue crystals in that oP 

 is small. Their axial ratio differs also, since a : b : c = .7834 : 1 • 

 1.2962. 



Weed and Pirsson 3 describe orthorhombic crystals of sulphur from 

 around the vents at the Highland Hot Springs and at Crater Hills in 

 the Yellowstone National Park, and stalactitic and fibrous growths of 

 orpiment and realgar in crevices of the rock surrounding vents in the 

 Western part of the Morris Geyser Basin in the same territory. 



Nesquehonite exists in the anthracite mine of Mure, Isere. Its 

 analysis by Friedel* gives results that prove its identity with the nes- 

 quehonite of Genth and Penfield. 



Syntheses.— While heating mica with soda and sodium sulphate 

 in a tube the mixture became dry, leaving a residue in which the 

 Messrs. FriedeP discovered little rhombohedra, with the composition 

 of nosean. Upon heating mica, soda and sodium carbonate for two 

 days at 500° the same experimenters obtained little hexagonal pyra- 

 mids of a substance with the composition 3 (2 Si0 2 , A1 2 3 , Na 2 0) + 

 Na, C0 3 + 2H 2 0, which the authors regard as a calcareous rich can- 

 crinite. If amorphous alumina be heated at 530° in a solution of soda 

 in a closed tube the excess of the first material will separate 6 upon cooling 

 as corundum. If heated at 400° diaspore is produced. When the 

 soda contains a little aluminum and calcium carbonates, calcite crystals 



