Viii PREFACE. 



all about the sulphides of metals, tellurides, &c., which 

 may be met with deeper in lodes or deposits. But he must 

 especially remember, that while he is to be busy with sur- 

 face matter, the mere study of rare and beautiful cabinet 

 specimens, with their perfect crystals, will be of compara 

 tively little use to him, 



February, 1897, 



