ART. 21 ORIGIlSr OF METAL IN METEORITES MERRILL 5 



way the slight amount of displacement sometimes shown by the sili- 

 cate particles (fig. 3, plate 1, and upper plate 2) could be accounted 

 for. It may be questionable, however, if under such conditions the 

 original tripartite character of the metallic alloys would not be de- 

 stroyed or disarranged. In the case of the Admire meteorite the 

 metal gives no visible indications of any such movement. 



It would seem scarcely necessary to consider the possibility of the 

 iron as having been introduced or injected in the ordinary condition 

 of molten fluidity. The melting point of pure iron is, as given, 1,530" 

 C. ; that of nickel 1,452° C. The pyroxenes, on the other hand, fuse 

 at approximately 1,400° C, and olivines at 1310°-1430° C. (accord- 

 ing to Doelter) . Apparently it could not then be a question of simple 

 dry fusion as the silicates would be reduced to the condition of slag — 

 " prof ondement desorganees," as Meunier expressed it. Existing 

 conditions can be explained, moreover, without assuming that the 

 metal has at any time been in a condition of fusion. Direct reduc- 

 tion of an ore as practiced in the early days of iron smelting, or as 

 still practiced in the well-known Catalan process, results in the pro- 

 duction at temperatures not above 700° or 800° C. of a spongy or 

 pasty mass of metal. It is easy to conceive that such material, com- 

 mingled with rock fragments and subjected for sufficient time to a 

 moderate pressure, might give rise to the structures described, par- 

 ticularly such as shown by the Four Corners iron." 



Another feature which may have a bearing upon the subject is 

 this. Meteoric irons almost invariably partake of the nature of the 

 so-called " wrought iron," in that they are soft and malleable. Ee- 

 ports to the contrary can be accounted for only on the supposition 

 that the material selected was a mixture. Some irons, like that of 

 New Baltimore, Pennsylvania, can be hammered down when cold; 

 others are more brittle but still malleable.^^ Fused in an ordinary 

 gas furnace in the laboratory these soft irons yield a bead no longer 

 malleable but hard and brittle like ordinary cast iron and with an 

 entirely different microscopic structure.^* (See pi. 3.) 



" I am indebted to Prof. Albert Sauveur, of the Harvard Engineering School, to whom 

 I sent a photograph of the slice shown in fig. 4, pi. 1, for the following suggestion : 



" The structure to which you call my attention recalls somewhat that of wrought iron, 

 in which we also find particles of silicates em'bedded in an iron matrix. This results 

 from the fact, as you undoubtedly know, that in the manufacture of wrought iron the 

 reduced metal is not melted, but remains pasty, retaining some of the liquid silicates or 

 slag very much as a sponge retains water. Also, just as further cooling of the sponge 

 results in particles of ice within the sponge, so further cooling of the wrought Iron results 

 in particles of silicates within the iron matrix. I wonder whether such a process might 

 have been at work in this caso ? It would, of course, imply reduction of an iron oxide or 

 of an iron salt at such low temperature that the reduced iron remains below its melting 



point." A I A 



"The United States National Museum collections contain two knife blades 7 and 14 



inches long hamm'ered out of the Coahuila and Nejed irons, respectively, by our local 



blacksmith in a small charcoal forge. Though easily shaped they could not be tempered. 

 " These experiments have not been carried far enough nor with sufficient refinement to 



allow the drawing of safe conclusions other than those mentioned. 



