410 Dr. Walter Flight— History of Meteorites. 



This mineral withstands the action of strong acids, is unchanged 

 when fused with potassium carbonate, and possibly when heated 

 with the chlorate ; heated in dry chlorine it glowed for a few seconds, 

 lost its metallic lustre, and left a residue which soon began to deliquesce. 

 The amount, about O002 gramme, was too small for anything but 

 a qualitative examination, which showed it to consist of calcium, 

 sulphur, and an element which gives the reactions of titanium * or 

 zirconium, probably the former, in some singularly stable state of 

 combination. By heating zirconium to an intense heat with lime 

 and aluminium, Mallet 2 obtained a golden-yellow incrustation, cubic 

 in form, unattached by the strongest acids, and possibly analogous 

 in its nature to.osbornite. 



The next mineral described is an augite of a pale violet-grey 

 colour, intimately mixed with another silicate presently to be de- 

 scribed ; it belongs to the oblique system, the measurements yield- 

 ing the following approximate values : 



Diopside. 

 001, 100 = About 75° 30' 73° 59' 



001, 110 = „ 81° 79° 29' 



110, 100 = 45° 54' to 47° 26' 46° 27' 



110,110 = 5° 8' to 86° 20' 87° 5' 



100, 111 ? = 53° 25' to 54° 15' 53° 50' 



001, 110 = 100° 81' 100° 57' 



The plane containing the optic axes is perpendicular to the edge 

 [100,001], and the optical character in the centre of the field is 

 negative. When looked through in any direction parallel to the zone 

 circle [001,010], the crystals show a remarkable dichroism; the plane 

 100 presents a somewhat facile cleavage, and is also conspicuous for 

 a remarkable metallic lustre, recalling that seen on some kinds of 

 diallage, but of a fine golden hue. The author is of opinion that 

 osbornite may permeate the augite in minute interlaminated layers of 

 sufficient thinness to be transparent. 



Two analyses of this mineral gave the following numbers : 



I. II- (| Mg | Ca) Si0 3 



Silicic acid 55-389 ... 55-594 56-604 



Magnesia 23-621 ... 23-036 23-585 



Lime 20-020 ... 19-942 19-811 



Iron oxide 0-780 ... 0-309 — 



Soda 0-554 ... [0-554] — 



Lithia trace ... [trace] — 



100-364 99-435 100'COO 



The iron oxide contains some of the titan oid metal met with in 

 osbornite. In terrestrial varieties of augite the calcium is usually 

 in excess of the magnesium. The mineral was somewhat soluble in 

 acid, the action, however, was found to be simply that of a solvent. 



While the augite is present in greatest quantity in the area 

 containing the calcium sulphide, it is met with in other parts of the 

 stone ; and associated with it everywhere, and forming the mass of 



1 See researches on the presence of titanium vapour in the solar prominences and 

 chromosphere, by C. A. Young. Amer. Jour. Sc, 1871, ii. 335. 



2 J. W. Mallet. Amer. Jour. Sc, 1856, xxviii. 346. 



