PAET VI. 



MINERALOGY AND GEOLOGY. 



CONTENTS. 



I. CKYST ALLOGRAPH Y. 



MODELS OF CRYSTALS. 



A. Wire Models - 1 



B. Glass Models - ... 3 



C. Models in other Transparent Substances - 5 



D. Wood Models - - -5 



E. Models in Cardboard - 6 



F. Crystal-Nets for making Cardboard Models - 8 



G. Miscellaneous Models, &c. - - 9 



II. INSTRUMENTS USED IN MINERALOGICAL AND GEO- 



LOGICAL RESEARCHES. 



A. Goniometers - - 9 



B. Instruments for investigating the Optical Pro- 



perties of Minerals - 12 



C. Petrographic Microscopes - 18 



D. Petrographic Microscopes for Students - 22 



E. Apparatus for cutting Sections of Minerals 



and Rocks - - - 23 



F. Apparatus used in Blowpipe Analysis - 25 



G. Apparatus for determining Specific Gravity - 26 

 H. Clinometers and other Instruments used in 



Geological Surveying - - 30 



III. GEOLOGICAL MODELS ILLUSTRATING VOLCANIC ACTION 31 



IV. SEISMOGRAPHIC APPARATUS - - 32 



V. SETS OF MINERALS, ROCKS, FOSSILS, AND MICRO- 



SCOPIC PREPARATIONS FOR TEACHING PURPOSES - 37 



U 69149. 1500 & 6. 1/92. Wt. 21621. ^ 2 



