350 Mr. C. T. Jackson's Chemical Afialysis of Meteoric Iron, 



at pressures Jess than those of the atmosphere. Eighteen 

 experiments were performed, at pressures included between 

 27'208 and 12'583 inches of mercury, and the results were 

 found in very close accordance with his formula; but less 

 than the numbers deducible from the theoretic expression 



fy* = c/— -) '' t given by Poisson in his Traite de Meca- 

 nique, tom. ii. p. 649. 



XLVII. Chemical Analysis of Meteoric Iron, from Claiborne, 

 Clarhe County, Alabama. J5j/ Charles T. Jackson. f 



Aug. 5, IVT'^' ^* ^LGER handed me this remarkable 



1834. -^ ■*■ mineral, which he had received from Mr. 

 Hubbard, who had obtained the specimen during his travels 

 in Alabama, and thought, from the bright streaks in it, that 

 it might be an ore of silver. 



On examining this substance, it soon appeared that it was 

 different from any metallic ore of terrestrial origin, and that it 

 is a very peculiar and remarkable meteorite. 



Having surmised its probable origin, I was desirous of see- 

 ing the gentleman who brought it from Alabama, and at the 

 request of Mr. Alger, Mr. Hubbard called upon me and gave 

 me the following particulars as to its locality. 



He found the specimen on the surface of the earth, near 

 Lime Creek, in Claiborne, Alabama. The soil at that place 

 is composed of red marl, or clay, and the rocks in place are 

 sandstones, mostly of a gray colour. The mass from which 

 my specimen was broken, was of an irregular triangular shape, 

 rounded at the corners, and was 10 inches long by 5 or 6 

 inches in thickness. It was extremely heavy, insomuch that 

 he could not conveniently carry with him the whole mass, and 

 therefore employed a negro to break it with a sledge-ham- 

 mer; which operation proving too difficult for him, Mr. 

 Hubbard took the sledge himself, and with the cutting edge, 

 by many hard blows, he ultimately succeeded in detaching 

 the portion in my possession. It is much to be regretted that 

 he did not bring with him the whole mass, and I desired him 

 to send for the remainder, but have not yet heard from him. 

 He is of opinion, that there are many other similar masses 



* In this expression y is the specific heat of air under a constant press- 

 ure when the height of the barometer is p, c the same when the height is 

 P, and K is the ratio between the specific heat of air under a constant 

 volume and a constant pressure. 



t From Silliman's American Journal of Science and Arts, vol.xxxiv. p. 332. 



