Chemical Science. 411 



The mass of Aix-la-Chapelle contains Iron, a little arsenic, 

 traces of charcoal and of cobalt, and perhaps of sulphur. The 

 mass taken from beneath the pavement in 1762 is evidently the 

 produce of art. Polyxene, or the black grains found in a par- 

 ticular sort of platina, are simply metallic iron, without any 

 mixture of other metals. The iron from Portuguese America, 

 composed of crystalline grains, and which is very rare, con- 

 tains a little copper and cobalt, and perhaps a trace of chromi- 

 um and manganese. This latter iron was obtained from M. Kru- 

 senstern, and M. John found a similar kind in the mineralogical 

 collection of Zurich, which, according to the table, had been 

 brought by M. Peterson from Kamtschatka. 



Having pulverized some meteoric stones, and obtained the iron 

 from them by means of a magnet, M. John analyzed it for the 

 purpose of comparing it with the analyses already mentioned. 

 The results were as follows : 



Iron (roni the Aerolite nrnAi.i™ nrci,„., 



ofChatonnay. Ofl'Aigle. Of Slenne. 



Iron . 92.72 . 92.72 . 92.72 



Nickel . 5.5 . 5.5 . 5.1 



Sulphur . 1 ') 



Cobalt . 0.78 ^Quantities too small to be weighed. 



Chrome . trace J 



The conclusions drawn from these experiments are, 1. That the 

 iron of meteoric stones and of the large ductile masses mentioned, 

 contain the same substances; namely, iron, nickel, cobalt, 

 chrome, and perhaps also manganese, as in that from Ellbogen. 

 2d. Iron of meteoric stones contains less nickel than the large 

 masses of soft iron. 3. Iron of meteoric stones evidently con- 

 tains sulphur, but probably not in combination with the whole of 

 it, but forming magnetic pyrites disseminated through it. The 

 large masses found in the earth contain no sulphur. — Ann. de 

 Chim. xviii. p. 198. 



6. Tests for Arsenic. — Dr. Porter, of the University of South 

 Carolina, in observing on the tests for the detection of arsenic, 

 remarks, that an appearance, similar to Scheele's green, is pro- 

 duced by carbonate of potash, added to a solution of copper 

 containing cofteo, but without arsenic, more striking than if a 

 weak solution of arsenic be used. He also states that, in the 

 production of Scheele's green by arsenic, sulphate of copper 

 and carbonate of potash, chromate of potash might be substi- 

 tuted for the arsenic ; and that the precipitate produced could 

 not be distinguished by the eye from Scheele's green. Also that 

 Mr. Hume's test of the nitrate of silver (as modified in its ap- 



ftlication by Dr. Marcet,) gave, with chromate of potash, a yel- 

 ow precipitate, which, when placed side by side with one pro- 

 2 E Si 



