Meteoric Stone which fell at the Mission Station of St. Mark's. 9 



contain silicates — olivine and enstatite — porphyritically developed. 

 In one case a nickel-iron chondrule can be seen enclosing a small 

 enstatite chondrule (Plate III., Fig. 4). The particles of nickel iron 

 are often quite structureless, but an actual intergrowth between the 

 silicates of the matrix scarcely occurs, so that they do not give the 

 impression of a later formation. 



Iron pyrites, v^hich the chemical analysis shows to be abundant, 

 seems to occur in small particles only, or at any rate there are none 

 large enough to show the characteristic lustre in reflected light. 

 Here belong, in the first place, the opaque particles in the silicates 

 and chondrules, since no copper separates out when the slide is 

 treated with copper sulphate, and the pulverised stone remained 

 dark after 17 per cent, of nickel iron had been extracted in vacuum 

 by means of ammonium mercuric chloride. Secondly, the iron 

 pyrites may often occur intergrown with nickel iron ; at any rate 

 there is frequently seen, by strongly reflected hght, a narrow border 

 which has not the bluish sheen of pure iron. 



Most of the chondrules are either perfectly spherical or nearly 

 so ; other forms, such as elongated ones, being rare. Fragmental 

 aggregates are scarcer than usual, and, as already stated, I do not 

 take them here — at least, not as a rule — for fragments of once 

 perfect chondrules. Indented chondrules are often to be seen (see 

 Plate III., Fig. 4, Meteoritenkunde, Heft ii., 37-38. Stuttgart, 1903). 

 The various deductions which have been drawn from such occur- 

 rences I have brought together and discussed in my Meteoritenkunde. 

 The dimensions of the chondrules are usually insignificant, averag- 

 ing not more than ^ to |^ mm. in diameter ; those ranging up to from 

 ^ to f mm. are not frequent, and larger ones are quite rare. The 

 total number is certainly greater than one would have expected from 

 the microscopic examination, but not as great as in the other black 

 chondritic meteorites of which it was possible to obtain sections 

 for comparison. Common to all chondrules are the interspersed 

 opaque ores, among which apparently iron pyrites predominates. 

 The proportion of these varies very greatly. The distribution is, as 

 a rule, fairly uniform, but there are occasional concretions in which 

 the narrow polysomatic border, free from inclusions, is clearly 

 differentiated from an opaque or very dark kernel. 



The constituents of the matrix are everywhere large enough to 

 determine easily, except, indeed, where there is much of the opaque 

 ore. The matrix thus shows what for a chondritic meteorite is a 

 well-defined and coarsely crystalline structure. Very noteworthy is 

 the absence of dust-like particles of silicates, as the result of which 



