140 On Crystallized JVatim Terrestrial Iron, ^e, 



Essore in France, where, during the trituration of a gunpowder, of 

 this description, although it was conducted with all possible care, bb 

 explosion killed several persons. 



Fulminating mercury, and fulminating silver are still more irritable, 

 and the latter, when thoroughly dry, will not permit even the weight 

 of a knile blade to rest upon it, without inducing a violent explosion ; 

 in a quantity equal to a common musket charge of gunpowder, it 

 would, probably, be always fatal.* 



7. It is not therefore theoretically improbable, that the heat ne- 

 cessary to the action of the oxygen upon the combustibles in gun- 

 powder, may be evolved by pressure, and the particles may also be 

 brought within the distance of effectual attraction, by the blow ap- 

 plied in ramming dow^Uy and thus it is possible, that the action may 

 come on, even when there is no spark, f May not some of the pre- 

 mature explosions of cannon and other fire arms be attributed to simi- 

 lar causes, especially when the piece is hot, in consequence of pre- 

 vious firing, although there should be no spark I 



All these views conspire to render it highly desirable that Mr. 

 Blake's method should prove successful, and I shall be much inter- 

 ested to learn the result, which, after sufficient experience, I shall 

 hope that you v/ill communicate to the public. I remain respect- 

 fully, your very obedient servant. B. Silliman, 



Yale College, Sept. 17, 1823. 



Art. XV^. — On Crystallized JVative Terrestrial Iron, Ferro-silicate 

 of Manganese, and various other American Minerals; by 

 Charles U. Shepard, Assistant to the Professor of Chemistry, 

 and Lecturer on Botany, in Yale College. 



1. C?'ystallized JVative Terrestrial Iron, 



In looking over a suite of rock specimens collected by Prof. Olm- 

 sted, Vi^ith a view to illustrate the Geology of North Carolina, and 

 deposited by that genderaan in the cabinet of the American Geologi- 

 cal Society, my attention was arrested by two pieces of Native Iron. 

 Of one of these, the larger of the two, an account is given in Prof. 



* I had neai'y lost both my eyes in ISll, by the explosion of fulminating silver., 

 which took place in consequence cf gentle pressure, even when it was under fluids-. 

 The paiiiculars of the accident arc related in Dr. Eruce's Journal, Vol. I. 



+ As iu the cases that occurred in France and which have been cited by Mj-, Blake^- 



