28 GEOLOGICAL MEMOIRS. 



on the meteoric iron of Pallas, well-known and repeatedly analysed 

 by distinguished chemists, and in reality I have found in it both cop- 

 per and arsenic ; also in the Mexican meteoric iron of Yuanhuitlan, 

 near to Oaxaca, brought home by my colleague M. Sommerschu, 

 principal engineer of mines ; in a meteoric iron from Tennessee, de- 

 scribed by M. Troost in Silliman's Journal ; and finally in a frag- 

 ment of the great mass of meteoric iron deposited in the Museum of 

 Natural History of Yale College in Connecticut. Consequently it is 

 not only at the surface of the earth that iron is mixed with copper 

 and arsenic, but also in the solid portions of other celestial bodies. 



"The results of these researches are highly deserving of attention. 

 In regard to the ores of iron, they particularly claim that of the 

 worker in iron : in regard to mineral waters, they may explain certain 

 peculiar effects of celebrated springs : finally, in discovering these two 

 poisonous minerals in earthy substances, in clays and cultivated soils, 

 they have a manifest interest for all those persons who occupy them- 

 selves with researches in medical jurisprudence ; and for the interests 

 of humanity and justice they are altogether indispensable." 



J.N. 



