CONTENTS. 



PACK 



Alum. Borax. Common salt. Nitrate of soda ; phosphate 

 of lime ; heavy spar ; fluor spar ; carbonate of lime. Precious 

 stones and gems ; diamond; table of characteristics of various 

 precious stones and gems 84 



CHAPTER VII. 



COMPOSITION OF VARIOUS ROCKS. 



Granite. Schists. Gneiss. Serpentine. Basalt. Pitchstone. 

 Obsidian. Pumicestone. Sandstones. Limestones. 

 Dolomite. Clays. Nature of certain minerals in igneous 

 and metamorphio rocks ; quartz ; felspar ; mica ; talc ; 

 chlorite; hornblende; augite; olivine. Matrices of veins ; 

 quartz ; fluor spar ; calc spar 99 



CHAPTER VIII. 



TESTING BY THE WET PROCESS. 

 Systematic plan of procedure . . . , , . .106 



CHAPTER IX. 

 ASSAY OF GOLD. 



Various methods. Fluxes, reagents, &c. General treatment of 

 ores. Preparation of the sample. "Weighing, &c. Assay 

 ton. To construct a simple button-balance and to use it. 

 Dry assay for gold and silver. Apparatus and procedure. 

 Fusion in a crucible. Scorification. Cupellation. Indica- 

 tion of the presence of metals known from cupel stains. To 

 make cupels. Dry assay for lead in galena. Wet assays for 

 gold, silver, lead, copper, iron. Roasting. Mechanical 

 assay of ores HO 



CHAPTER X. 



TREATMENT OF ORES. 



Metallurgical treatment. Copper from copper pyrites and other 

 sulphides. Lead from galena. Treatment of silver-bearing 

 ores Gold from lodes and deposits. Concentration of ore . 124 



