XVI. Observations and experiments on the mass of native iron 
found in Brasil. By W. H. Wollaston, M. D. Sec. R. S. 
Read May 1 6, 1816. 
The preceding letter from Mr. Mornay, relating to the 
discovery of a mass of native iron in Bahia, was drawn up at 
my request^, as a valuable addition to our stock of knowledge 
on that most curious subject; and I am in hopes that the 
results of my own experiments may contribute something 
not uninteresting to the Society. 
The specimen of the iron with which Mr. Mornay very 
liberally supplied me for experiment, though it necessarily 
bears marks of the hammer by which it has been detached, 
presents also other surfaces, not only indicating that its tex- 
ture is crystalline, but showing also the forms in which it is 
disposed to break, to be those of the regular octohedron and 
tetrahedron, or rhomboid, consisting of these forms combined. 
In my own specimen, the crystalline surfaces appear to 
have been the result of a process of oxidation, which has 
penetrated the mass to a considerable depth in the direction of 
its laminae ; but in the specimen which is in the possession of 
the Geological Society, the brilliant surfaces that have been 
occasioned by forcible separation from the original mass, ex- 
hibit also the same configurations, as are usual in the fracture 
of octohedral crystals, and are found in many simple native 
metals. 
The magnetic qualities of the fragments, fortunately, 
