ACADEMY OF NATURAL SCIENCES. 49 



The dimensions of this ring are as follows : 



Greatest exterior diameter 49 inches. 



Least exterior diameter 38 " 



Greatest width of central opening 26* " 



Least width of central opening 23 " 



Greatest thickness at right angles to plane of ring 10 " 



Width of thickest part of the ring 17^ " 



Width of narrowest part 2f " 



The weight of the mass corresponds, taking the specific gravity at 7.2, with 

 a circle-ring, having an average width of one foot, and a thickness of a small 

 fraction less than eight inches — the diameter of the circle represented by the 

 exterior of the ring being assumed as four feet. 



On examining with a magnifying glass a fractured surface of the mass, it was 

 seen at once to be different in composition from the Carleton Meteoric Iron, and 

 my conjecture that Prof. Smith was mistaken in supposing that he analyzed a 

 fragment from the mass figured by Mr. Bartlett, was confirmed.* It is now 

 almost certain that Messrs. Brush and Smith did analyze fragments of the same 

 meteoric iron. 



The Ainsa Meteoric Iron contains a large per centage of a white — almost 

 transparent — silicious mineral, having a vitreous lustre, which may be olivine ; 

 but the amount seems larger than that in the Carleton mass. The Smithsonian 

 Institution will undoubtedly cause a chemical investigation to be made of this 

 superb meteoric mass, and it will be interesting to compare its composition with 

 that of the Carleton meteorite, as the two were found so near each other that 

 they may be supposed to have formed portions of the same body, and to have 

 fallen at the same time. 



The photograph was taken by Mr. Watkins, at my request, partly to be sent 

 abroad as a specimen of the high degree of perfection which has been attained 

 by this gentleman in this department of art, and partly that an exact repre- 

 sentation might be secured of this very remarkable body, in case it should be 

 lost or captured on its way to Washington. 



In concluding this notice, the following statement is given of all that is 

 known of the size and position of the masses of meteoric iron which have been 

 noticed by various travelers in Arizona and the adjacent portions of Mexico 

 and New Mexico. 



In the Madera range, " Sierra de la Madera," between Tucson and Tubac, 

 "enormous masses of pure iron, some of which were transported to Tucson, and 

 for many years were to be seen in the Plaza of that Presidio." Francisco 

 Velasco, in W. F. Nye's Translation of his work on Sonora, p. 146, published 

 at San Francisco in 1861. — Two of these masses have been brought to this 

 city, the one weighing 1,600, the other 632 pounds; the question arises, how 

 many more are left in the Sierra Madera ? To this, no answer can be given at 

 present. 



Pro. Cal. Acad., vol. hi. 



*See page 34, of this volume. 

 4 Sept. 1863. 



