INDEX TO PART IV. 



Page. 



Absorption of light by crystals, . i6 



Acidic eruptive rocks, . . . i44 



Acidic unstratified rocks, . • ^73 



Actinolite, 60 



Actinolite schist 232 



Age of greenstones, . • • 236 



Albany granite, .... 198 



Albite, 98 



Almandite, 72 



Alteration of basic eruptive rocks, . 149 



Alum 126 



Amazon stone, .... 102 



Amethyst, 49 



Amorphous bodies, optical properties 



of 10 



Amphibole, 60 



Amphibolite, 230 



Analcite, 112 



Analysis of albite, .... 98 



" andesite, ... 96 



" anorthite, ... 91 

 " anorthite diabase, . .156 



" argillitic mica schist, . 219 



beryl, .... 69 



biotite, . . . • 79 



" chalcopyrite, ... 33 



" chlorophyllite, . . 78 



" chrysolite, ... 70 

 " columbite, . . .122 



" danaite, ... 34 



" diabantite, . . . 120 



" diorite — eruptive, . . 161 



♦« diorite — metamorphic, . 228 



" galenite, ... 28 



" garnet, . . • • 72> 



" hematite, ... 38 

 hornblende, . . 63, 64, 65 



«' infusorial earth, . . 52 



iolite, . ... 77 

 '< labradorite, . . 93, 95 



" magnetite, ... 41 



" micaceous diabase, . 153 

 " mountain cork, . -US 

 VOL. IV. 32 



Analysis of olivine, . 

 orthoclase, 



" pargasite, 



" prochlorite, 



" pyroxene, 



" quartz porphyry, 



" sphalerite, 



" staurolite, 



" tourmaline, 



" triphylite, 



" zircon, . 



Andalusite, 



" alteration to cyanite 



" mica schist, 



Andesite, 

 Andradite, 

 Ankerite, 

 Annite, . 

 Anorthite, 



Anorthite diabase, . 

 Anthophyllite, 

 Antrim granite. 

 Apatite, . 



Argentiferous galena, 

 Argentine, 

 Argentite, 

 Argillite, . 



Argillitic mica schist, 

 Arsenic (native), 

 Arsenopyrite, . 

 Asbestus, 

 Augen gneiss, . 

 Augite, . 



associated with hornblende 

 " in quartz porphyry, 

 " optical properties of 

 " sienite, 

 Autunite, 

 Azurite, .... 



Barite, . 

 Basic diorite, 



Page. 

 70 

 100 



65 



119 



63, 64 



178 



30 

 109 

 104 

 I2S 



75 



105 



106 



216 



96 



72 



130 



82 



90 



60 

 196 

 122 



28 

 127 



27 



218 



25 



61 



214 



54 

 162 

 180 



15 

 205 

 126 

 131 



126 

 160 



