46 Di'. Nceffoeiath on the 



os^ 



like this, greater and lesser cavities, on the surface of which 

 some crystalline appearance is found ; but never, as far as I 

 know, a filling-up of olivine or any other mineral substance. 

 Among all the fragments of meteoric iron in my possession, or 

 that I have ever seen, I found none so greatly resembling the 

 fragment of Bitburg described here, as that from the Mon- 

 tanna de Santa Rosa in Colombia, first made known by Ma- 

 riano de Rivero ; a piece of which, weighing several ounces, 

 was presented to the university of Berlin by de Humboldt, 

 and of which I possess a fragment of about three drachms in 

 weight, They fully correspond as to colour, soilness and poro- 

 sity. On a smooth and etched surface of my fragment of the 

 Colombian metal, no regular figures are seen, but only a 

 slight indication of a crystalline structure ; nor would they, as 

 I think I may conclude from its external appearance and po- 

 rous state, appear in the fragment of the Bitburg iron : nor 

 indeed can it be expected from such porous pieces of the ex- 

 tremities of the mass ; but certainly towards the interior, where 

 the structure is closer and more crystalline. 



Concerning the grains of an earthy substance found in the 

 cavities of the Bitburg iron, either singly or in aggregates, I 

 imagine that they may have existed before its fall, and have 

 an affinity with meteoric stones. 



The difference of the quantities of sulphur in natural and 

 melted pieces, may originate from a mixture of iron pyrites 

 with the latter ; and also from the circimistance that in seve- 

 ral masses of native iron, the sulphureous iron is added to 

 the remaining mass in distinct parts, as I have shown in the 

 Annaleri der PJnjsik for 1822, which sometimes render it diffi- 

 cult to saw, and may cause a difference in the quantities of 

 sulphur found in the analyses. 



IX. On Meteoric Iron from Mexico. By Dr. J. Nceggerath. 

 In a Letter to Dr. Chladni*. 



Bonn, 25tli of June 182G. 



T AM now enabled to give you a better account of the place 

 -*- where that meteoric iron was found which I received 

 during your late visit to Bonn, and of wliich I had a small 

 fragment cut off for you. It was sent to the directors of the 

 German- American Mining Association at Ebberfeld, accom- 

 panied by a letter from their principal agent in Mexico, Mr. 

 W. Stein. — Mr. S. expresses himself in the following terms : 



* From Stiiwcigger's Joiunal, N. K. Band xvii. p. 74. 



" Among 



