358 



SCIENTIFIC INTELLIGENCE. 



MINERALOGY. 



1. Native Metallic Iron. — Dr Andrews, in an examination into 

 the minute structure of basalt, has found evidence of the existence of 

 iron in a native state. After pulverizing the rock, and separating 

 with a magnet the grains that were attracted by it, he subjected 

 these grains, which were mostly magnetic iron, to the action of an 

 acid solution of sulphate of copper in the field of a microscope. 



This salt produces no change with the oxide, but if a trace of 

 pure iron be present, copper is deposited. In his trials there were 

 occasional deposits of copper in crystalline bunches ; the largest of 

 which obtained was little more than one-fiftieth of an inch in diame- 

 ter. He observes that with 100 grains of the rock, three or four de- 

 posits of copper can usually be obtained. The basalt of the Giant's 

 Causeway affords this evidence of the presence of native iron, but 

 less so than the Slievemish basalt. 



The same result would be produced, if the nickel or cobalt were 

 present in fine grains ; but Dr Andrews considers this very impro- 

 bable. The same basalt afforded, on microscopic examination, 

 augite, magnetic iron, pyrites, and a colourless glassy mineral. — 

 (American Journal of Science and Arts, vol. xv., No. 45, 2d 

 Series, p. 443.) 



2. On Glauberite from South Peru ; by M. Ulex. (Leon- 

 hard u. Bronn's N. Jahrb. f. Min. u.s.w., 1851, p. 204 ; and 

 Woehl. u. Lieb. Ann., vol. lxx., p. 51 et seq.~) — The Brongniartin 

 or Glauberite occurs in crystals imbedded in nodular masses of a 

 substance called " Tizza," which the author recognised as a bo- 

 racic compound. According to Frankenheim the crystals, attain- 

 ing a size from 1 to 1 \ inch (German), differ from those of Brong- 

 niartin previously known in their angles, but slightly however ; 

 the form also somewhat differs. Sometimes the crystals appear 

 perfect and transparent, sometimes white and laminated, the fis- 

 sures being occupied by the above-mentioned substance. Spec, 

 grav. = 2 64 ; hardness = 2*5 — 3-0. Its behaviour in the alembic 

 and before the blow-pipe, is like that of the Spanish Brongniartin. 

 An analysis gave — 



Lime, . . . . . . 19 6 



Soda, 21-9 



Sulphuric acid, .... 55'0 



Boracic acid, . . . . 3*5 



Formula : NAS + S + Ca S. 



The presence of borax is no doubt due to the admixture of the 



