C. U. Shepard on Meteoric Iron from Sonora. 371 
The acids act very tardily on the iron, and require to be aided 
by heat, before the action will fairly commence. No decided crys- 
talline structure is developed in the process; though the frag- 
ments experimented on, being small, and considerably altered in 
molecular texture by the force applied in their separation from the 
parent mass, it would not be safe from this trial perhaps, to con- 
clude against a crystalline structure in the main portion of the iron. 
p. gr. == 6°66, which corresponds very nearly with that of the 
Atacama iron, as determined by Turner, whose trial specimen no 
upon by acids; but here again, it would not be strange if this 
It remains only to state a few additional particulars concerning 
these iron-masses, derived from a later letter of Lieut. Parke, 
which he kindly permits me to annex to this notice. 
“'The three masses were found in a cafiada of the Santa Rita 
Mountain, about 25 or 30 miles to the south of Tuczon. Two 
of them were shown to us by the Commandante ; both being 
