1905.] NATURAL SCIENCES OF PHILADELPHIA. S75 



conceivable to me, as I have already stated, that this material could 

 have been produced in the quantities in which we find it in any other 

 way than by a heavy blow. 



Additional Argument AGAINST the Theory of a Steam Explosion. 



Eighth: Even if a steam explosion could have produced the silica 

 dust it would have blown, as Mr. Tilghman points out (see page 899), 

 such finely divided material high into the atmosphere, after the man- 

 ner of the great Krakatoa explosion in 1883, and a very large portion 

 of this material would certainly have been carried away by air cur- 

 rents and finally deposited far from the crater, instead of in the 

 crater or on the exterior slopes of the mountain immediately sur- 

 rounding it, where finely pulverized material is distributed in enormous 

 quantities in such a manner as to warrant the belief that it and the 

 rock fragments contained in it behaved not unlike a liquid when they 

 were expelled by some force out of the crater. Again, the dust or 

 minute particles or filaments of volcanic glass expelled from the vol- 

 cano of Krakatoa were not only certainly of igneous origin, but when 

 examined under the microscope were in every case found to be more 

 or less round in shape, instead of being sharply angular particles of 

 crystalline quartz, due, as is safely assumed, to the disintegration or 

 rather pulverization of sand grains. 



Since we have come into possession of the property we have found 

 several thousand pieces, in all something over a ton, of various sized 

 fragments of meteoric iron, the largest weighing as I remember 225 

 pounds, down to pieces weighing much less than an ounce or only a 

 few grains. These meteoric iron specimens (known to the scientific 

 world as the Canon Diablo siderites) are so well known that I shall not 

 attempt to describe them. The following analysis by Messrs. Booth, 

 Garrett and Blair, of Philadelphia, may be taken as representing the 

 general composition of these irons : Si 0.047 ; S 0.004 ; P 0.179 ; C 0.417 ; 

 Ni 7.940; Fe 91.396; total 99.983. In the present discussion it is far 

 more interesting to state that they have been found more or less con- 

 centrically distributed around the crater and to an extreme distance, 

 so far as we know, of two and one-half miles from it, a few small speci- 

 mens having been found in Canon Diablo gorge. It is a remarkable 

 fact that these so-called ' ' irons ' ' (to distinguish them from the so-called 

 "iron shale") are ver}^ angular in shape, indicating by their fracture 

 that they may have been violently torn off or burned from similar ma- 



