Dr. Walter Flight— History of Meteorites. 549 



shower of meteorites, believed by Breithaupt to have been the 

 "Eisenregen" which occurred at Whitsuntide, 11G4, in Saxony, 

 Avhen a mass of iron fell near the town of Meissen. 



A polished surface of either of these masses exhibits irregularly 

 formed patches of nickel-iron, the interspaces being partly filled 

 with small patches of iron sulphide, the greater portion of the 

 surface being occupied by a greenish and greyish-brown crystalline 

 magma. After the removal of the two first-mentioned ingredients 

 with mercury chloride, the magma is found to consist of (1) highly 

 crystalline, bright green or greenish-yellow grains; (2) rusty-brown, 

 sometimes nearly black, sometimes also nearly colourless grains of 

 a mineral presenting crystalline features, but on which definite 

 planes are rare ; and (3) crystalline grains of chromite. 



The first of these ingredients is bronzite, the crystallographic 

 characters of which are described in the paper of von Lang, who 

 gives the results of measurements made on nine crystals; these 

 results are mineralogically important as affording for the first time 

 complete data for the crystallography of a rhombic mineral having 

 the formula of enstatite. The elements of the crystal are : 



a : b i c = 0-87568 : 0-84960 : 1 

 which give the following among the important angles by calculation : 



110,010 = 44° 8' 



101,100 = 41° 11' 



011,010 = 40° 16'. 



Von Lang observed the following faces : 



100, 010, 001, 011, 054, 302, 101, 102, 103, 104, 410, 520, 210,530, 110, 120, 250, 



130, 111, 121, 112, 122, 212, 133, 232, 124, 144, 324, 344, 524. » 



The most important zonal relations of these faces are shown in 

 the spherical projection appended to his paper. 



The hardness of this mineral is 6 and the specific gravity 8-238, 

 a number differing but slightly from those determined by Stromeyer 

 and estimated by Rumler in the case of the silicates of the Steinbach 

 siderolite. The composition of the bronzite, as determined by analyses 

 made by the new method of distillation already alluded to (page 

 408) and by fusion with alkaline carbonates, was found to be : 



I. II. Mean. Oxygen. 



Silicic acid 56-101 ... 56-002 ... 56-051 ... 29-89 



Magnesia 30-215 ... 31-479 ,.. 30-847 ... 12-34 



Iron protoxide 13-583 ... 13-295 ... 13-439 ... 2-97 



99-899 100-776 100-337 



These numbers correspond very closely with the formula (Mg| Fet) 

 SiO s - This bronzite, which occurs in association with nickel-iron, 

 contains only half the amount of iron met with in the bronzite of 

 the Manegaum meteorite (page 403), which stone contains next to 

 no nickel-iron. Eammelsberg 2 has recently pointed out the fact 



1 About the time that von Lang published these results vom Eath measured some 

 crystals of terrestrial bronzite, found in a sanidine bomb from the Laachersee, and 

 arrived at results which accord very exactly with those of von Lang. {Pogg. Ann., 

 cxxxviii. 529.) 



2 C. Eammelsberg. Pogg. Ann., cxl. 311. Eammelsberg draws attention to the 

 remarkable accordance between the angles of bronzite and olivine, which would 

 explain the fact of G. Eose having regarded the silicate in the siderolites of Eitters- 

 griin and Steinbach as olivine. (See note to page 313.) 



