CONTENTS xiii 



Page 



Directions or axes of vibration of crystals , 256 



Use of converging polarized light 258 



Axial angles 258 



Polarization colors 260 



The selenite plate 260 



Absorption of light, pleochroism 263 



Measurement of angles and of extinction angles 264 



Characteristics of the six crystal systems 267 



Experiments with crystals 269 



CHAPTER XII. 



Methods for Handling Small Amounts of Material 



Testing for solubility 276 



Decantation 278 



The centrifuge. . 281 



Filtration 284 



Sublimation 288 



Distillation 292 



Ignition, fusion 296 



Grinding and mixing 297 



CHAPTER XIII. 



The Methods of Microchemical Qualitative Analysis. 



The various ways in which reagents are applied 298 



CHAPTER XIV. 



Characteristic Microchemical Reactions of the Common Elements and 

 1 Acids when in Simple Mixtures, 



Cations: 



Sodium 3 T 9 



Potassium 3 2 7 



Ammonium 33 l 



Calcium 333 



Strontium 33& 



Barium 34 1 



Calcium, strontium and barium, additional tests 34° 



Magnesium 35° 



Zinc 353 



Cadmium 3 02 



Mercury 3 6 4 



Lead . s 3»9 



Silver 37" 



