COMPOSITION AND STRUCTURE OF METEORITES 51 



these bodies and suggests that they may have been of the nature of 

 snail spawn jelly, at any rate of organic and terrestrial nature. In a 

 footnote to the article, reference is made to the observations of a 

 Mr. John Treat, who, while with the army of General Washington 

 during the Revolution, saw a shooting star fall within a few yards 

 of him. He immediately went to the spot and found there a gelati- 

 nous mass which "if we recollect right was still sparkling." Other 

 similar observations are given. There would seem no question, how- 

 ever, but that these were in all cases of an organic (fungoidal) nature, 

 and of terrestrial origin. 



A large share of these reported occurrences are doubtless due to the 

 observers having been mistaken in their identification of the fallen 

 material. 



Within but a few months the writer was interviewed by a person 

 who brought a sample of meteoric material "seen to fall" which 

 proved to be but a flat, widespreading fungoidal growth. No amount 

 of argument could convince the finder that he was in error. 



Meteorites are not themselves magnetic, but nearly all meteoric 

 irons will acquire strong and permanent magnetism, though this 

 property may be in part, not wholly, destroyed by heat. It may be 

 remarked here, as noted elsewhere ^ that in process of oxidation, 

 meteoric irons assume first a magnetic oxide stage before passing over 

 into the normal nonmagnetic sesquioxide. 



CHONDRITIC STRUCTURES IN TERRESTRIAL ROCKS 



The question is likely to arise, "Do these chondrules and chon- 

 droidal forms have any exact counterpart in terrestrial rocks?" The 

 answer, with the information available to-day, is "No." Neverthe- 

 less it will be well to consider a few cases which on first glance at 

 least, so closely resemble the meteoric chondrule as to merit attention. 

 Before entering upon this discussion it will be well, however, to refer 

 back, perhaps repeat in part, the writer's dictum to the effect that 

 only those chondrules with smooth surfaces, often indented and show- 

 ing internally amorphous, microcrystalline, radiate, or barred struc- 

 tures, may have the origin ascribed to them by vSorby — are cooled 

 drops of molten matter ha^^ng the chemical composition of enstatite 

 or of olivine. Those of a rough exterior and internally porphyritic 

 or holocyrstalline are products of the mechanical attrition of pre- 

 existing cooled rock masses.^" 



A most suggestive example of chondroidal structure in a terrestrial 

 rock is afforded by a " kugelgriinstein " found at Stefanschacht, 

 Schemnitz, Hungary. The stone is quite massive and of a light 



» Proc. U. S. Nat. Mus., vol. 24, 1902, p. 910. 



" Proc. Nat. Acad. Sci., vol. 6, no. 8, 1920 pp. 449-472. 



