1835.] Improvements in Science. 279 



of iron cannot be appreciated, on account of the quantity 

 of lead. 



Rose has never found platinum and gold associated. He 

 deduces from his analyses several important consequences. 



1 . Native gold does not contain gold and silver in defi- 

 nite proportions. 



2. Gold and silver being thus combined in indefinite 

 proportions, he concludes that they are isomorphous, an 

 inference which cannot be deduced with the same certainty 

 from the identity of their crystals. 



3. Native gold always contains silver, copper, or iron. 

 The smallest quantity of silver was in a specimen from 

 Schabrouski, which contained *16 per cent, of silver, but 



*35 per cent, of copper were present. 



4. The specific gravity is in the inverse ratio of the 

 proportion of silver contained in the mineral. 



In general, fused gold has a greater density than native 

 gold, which, however, may be owing to cavities in the latter. 



5. Different specimens from the same locality vary in 

 composition. 



6. Gold found in veins varies in different parts of the 

 same mine. 



7. He finds that the gold from sand contains more silver 

 than that from veins. The proportion in the former being 

 89*7 per cent, of silver, and in the latter, 79*1, a fact com- 

 pletely contrary to the determination of the Russian govern- 

 ment, for the mining of gold has entirely yielded to the 

 process of procuring it from sand. (Poggendorff Ann.) 



METEORIC STONES. 



According to Hofrath Stromeyer, copper exists in all 

 meteoric masses. He examined specimens from Agram, 

 Lenarto, Elbogen, Bitburg, Gotha, Siberia, Louisiana, 

 Brazil, Buenos Ayres, and the Cape of Good Hope, and 

 found in all of them an appreciable quantity of copper, 

 varying from 0*1 to 0*2 per cent., and he came to the con- 

 clusion that the presence of this metal must be considered 

 as constant a character of these substances as are the nickel 

 and cobalt, which are found in greater proportion. {Ann. 

 tier Physik, xxvii. 689.) 



Berzelius appears to have entirely overlooked this metal, 

 in meteoric stones, for, in the analysis of a mass from 

 Macedonia, he found 



