HANDBOOK OF THE METEORITE COLLECTIONS. 163 



Per cent. 



Nickel-iron 22. 78 



Troilite 4. 96 



Iron magnesian silicates 71. 88 



99.62 

 Reference.— O. Buchner, Die Meteoriten in Sammlungen, 1863, 

 p. 90. 



TUCSON, ARIZONA: THE SIGNET, IRWIN, OR RING METEORITE. No. 368. 



Iron, Dm. Weight of main mass 621,531 grams. Original mass 

 stated to have weighed 637,224 grams. In form of a complete ring. 

 Height, 97 centimeters; greatest width, 124 centimeters; width of 

 opening, 68 centimeters; greatest thickness of ring, 49 centimeters; 

 least thickness, 4.5 centimeters. (See pi. 1.) Date of fall unknown. 

 First calkd to public attention by Dr. John L. LeConte in 1851,* 

 and brought to the Smithsonian Institution in 1863, through the 

 influence of Dr. B. J. D. Irwin, U. S. A. The original source is 

 believed to have been the Pass of Los Muchachos, in the Sierra 

 de la Madera, whence it was brought by Spanish soldiers to the 

 old Presidio, where it remained until the withdrawal of the Spanish 

 garrison. It was then taken to Tucson and set up as a kind of 

 "public anvil for the use of the inhabitants." The mass was sent 

 in 1860 from Tucson to Hermosillo, and later to Guaymas. In 1863 

 it was taken to San Francisco and thence to Washington by way of 

 the Isthmus of Panama. 



The results of chemical analyses obtained by various investigators 

 are somewhat variable, as might be anticipated from material not 

 absolutely homogeneous. The following are the results obtained by 

 J. L. Smith, F. A. Genth, and G. J. Brush: 



Constituents. 



Smith. 



Genth. 



Brush. 



Iron(re) 



Nickel (Ni) 



Cobalt (Co) 



Copper (Cu) 



Phosphorus (P) , 



Alumina ( AI2O3) 



Llme(CaO) 



Magnesia (MgO) 



Soda(Na20) , 



Potash (K2O) 



Chromic oxide (CrjOj) . 



Silica (SiOs) 



Labradorite (?) 



Per cent. 

 85.54 

 8.55 

 .61 

 .03 

 .12 

 Trace. 



2.04 



.21 

 3.02 



Per cent. 



83.47 



9.44 



.42 



.008 



.10 



Trace. 



.46 



2.59 



(') 



(') 



(') 



2.87 



1.05 



100. 408 



Per cent. 



83.64 



9.85 



.15 

 Trace. 

 (') 

 2.15 

 .174 

 .098 

 .50 



4.17 



100. 732 



Per cent. 



81.65 



9.17 



.44 



.08 



.49 



Trace. 



1.16 



2.43 



3.63 



99.05 



1 Proc. Amer. Assoc. Adv. Sci., Albany meeting, 1851, p. 188. 

 » Not estimated. 



