Fusion- ^truetureH ii/ Meteorites. 307 



tion is shown, not even '' aggregut-poliiriziition!" Hence they 

 can l)e neither simple minerals nor crystals, least of all could 

 the structure be explained by lamellar fracture. This fact, — the 

 optical behavior, — should alone have led to the correct interpre- 

 tation." 



This statement is truly remarkable, and if this argument be 

 intended to serve as keystone to the whole structure of theory 

 and observation (:), this structure mu«t fall, for tlie keystone 

 is Avorthless. 



In the first place, the sti'uctures that I found in meteorites 

 du polarize light ; and, secondly, true fossil structures of organic 

 origin, crinoids, sponges and nummuHtes, which I tested, also 

 l)olarize light ; so, even if the statement that these inclosures 

 do not polarize light, should be granted to be true, even then 

 I fail to see how an organic origin can be claimed for them on 

 the strength of this, when true organized structures of the kind 

 under consideration ^josse^s tlie property of polarizing ! 



And so, being convinced that the existence of these fusion- 

 structures could not be ascribed to the agency of life, I con- 

 tinued my Avork in the hope of discovering some clue or data 

 that would serve to unravel the mystery of their formation. 



The next step taken was the examination of tc^rrestrial igne- 

 ous rocks, some of which show a similarity of composition with 

 meteorites. 



Besides rliyolite and basalt, there were examined — 



A. Scoria from Sandwich Islands. 



B. Scoria from Las Yalles, Is'ew Mexico. 



C. Tufaceous trachyte, Lightliouse Rock, Colorado River. 



D. Lava from Mount Vesuvius. Italy. 



E. Lava from Vesuvius. (Different external ajipearance.) 



F. Lava from Mount Vesuvius. (Different specimens.) 



From these six latter specimens, I had in all, thirteen sections 

 made, obtaining in each case longitudinal and transverse cuts. 



In A, C, E and F, fusion-structures were found ; D did not 

 show them, while B exhibited, very perfectly, the true microli- 

 thic structure. 



On Plate XXI will be found several of the most character- 

 istic fusion-structures observed in some of these. 



