352 On the Paragenetic -Relations of Minerals. 



galena is found covered with a crust of galena, in small in- 

 dividuals, such as are never found elsewhere, and more fre- 

 quently entirely converted into galena, while its form is re- 

 tained (Blaubleiertz). 



The entire removal of the minerals, such as is observed at 

 Gbpersgrun is certainly one of the most remarkable pheno- 

 mena known. Steatite occurs here in the form of quartz, 

 fluorspar, a carbonate, and a nodular mineral, perhaps kalk- 

 schwerspath, which formerly constituted the lode. Every 

 trace of silica, carbonate, &c, has disappeared, and silicate 

 of magnesia is found in their place. The silica of the quartz 

 and the magnesia of the carbonate cannot have contributed 

 much to the immense masses of steatite. This change has 

 most probably been very gradual, and may have been caused 

 by springs containing silica and magnesia. 



There are certainly changes observable in lodes which 

 cannot be explained on known chemical principles. Time 

 appears almost without question to have exercised a most 

 important influence in their production ; and there can be no 

 doubt that chemical processes are continually going on in 

 the mineral masses which constitute our globe, so gradual 

 in their action as to be imperceptible, and perhaps even un- 

 suspected by the chemist, but whose results are, in point of 

 magnitude, out of all comparison with such as he is able to 

 observe and set in action in his laboratory. 

 (To be continued in our next.) 



Anniversary Address to the Ethnological Society of London. 

 By Sir Benjamin C. Brodie, Bart. 



Mankind, scattered as they are over the entire surface of 

 the globe ; located among the perpetual snows of the Arctic 

 regions, and in the perpetual summer of the Equator ; on 

 mountains and in forests ; in fertile valleys and in deserts ; 

 in lands of rain and tempests ; and in those which are never 

 or rarely blessed by descending showers — are presented to 



