380 Scientific Intelligence. 



protoxide of iron -1593, magnesia -0360, potash -0140, soda -0042, 

 water -0584, insoluble quartz •3420=1-1869. This calculated for 

 100-00 parts of the silicate gives as follows; silica 38-93, alumina 

 28-88, protoxide of iron 18-86, magnesia 4-25, potash l-d9, soda 

 0-48, water 6-91. The analysis of another portion of -526 grams 

 by fusion with an alkaline carbonate gave, by calculation for the 

 silicate, 18-80 of protoxide of iron, and amounts of alumina and 

 combined silica closely agreeing with those found above. The 

 oxygen ratio for §i,_K, 5,3, is as 20-77 : 13-46 : 6-29 : 6*14, or nearly 

 as 3 : 2 : 1 : 1. This mineral approaches closely in composition 

 to joUyte, but differs from it in containing a portion of alkalies, 

 and but one half as much water. In these respects it agrees 

 closely with a silicate found by Robert Hoffmann with the Lau- 

 rentian Eozoon of Raspcnau, (Jour, filr prakt. Chem., May, 1869, 

 and this volume, page 378), This latter is compared by Hoff- 

 mann to fahlunite, to which species also jollyte is allied in phys- 

 ical characters as well as in composition (Dana's Mineralogy, 

 page 493.) Under the names of fahlunite, pinite, etc., is included 

 - "class of hydrated silicates, which, from their imperfeo' 



) admit that silicates found in the condition described , 

 Hoffmann, and still more the present mineral, which injects the 

 pores of paleozoic crinoids, can *)e any other than original deposi- 

 tions, allied in the mode of their formation to the serpentine, py- 

 roxene and other minerals which fill the chambers and canals of 

 the Laurentian Eozoon, and to the glauconite which occurs in a 

 similar manner in Tertiary and recent shells. The limestone from 

 Woodstock, apart from the insoluble matters just described, is 

 very pure, yielding only 1 -80 p. c. of alumina and iron-oxide, and 

 magnesia equal to 1-35 p. c. of carbonate. 



Montreal, March 10, 1871. 



3. On native amorphous Mercuric Sulphide.— G. E. Mooeb has 

 recently examined a specimen of black mercury-ore collected lu 

 Lake county, California, by Professor Whitney. It occurs as a 

 coating on the sides of cracks and crevices in a peculiar quartzose 

 gangue, and is accompanied by crystallized and massive iron and 

 copper pyrites, and very minute cochineal-red crystals of cinnabar. 

 Its physical properties are thus given :— BJntirely without structure 

 or cleavage. Fracture semi-conchoidal to uneven, fracture-surtaees 

 brilliant. Very brittle when struck or bent, yet tough when cut. 

 Rubbed in an agate mortar the powder becomes a solid ma^S 

 taking a high polish and a metallic luster like graphite, toior 

 grayish-black. Luster metallic. Streak on porcelain pure blacK. 

 Cut surfaces brilliant. Hardness about 3 on Mohs's scale, sorn^ 

 what greater than cinnabar, though difficult to estimate exaaiy 

 on account of its brittleness. Specific gravity 7-701 to 7 z", 

 somewhat different in different specimens on account of ®"i^^, 

 cinnabar. Before the blowpipe it behaves like cinnabar. ^^^ 

 closed tube, it sublimes completely, with the exception of a tri ^ 

 residue of quartz and iron oxide. The black sublimate yieias ^ 



