viii CONTENTS 



CHAPTER III. 



ILLUMINATION or OBJECTS; ILLUMINATING DEVICES. 



PAGE 



Different modes of illumination 30 



Transmitted light 30 



Condensers, Abbe condensers 32 



Reflected light 37 



Dark-ground illumination 40 



Dark-ground illuminators 41 



Objectives for use with dark-ground illuminators 43 



Resolving power with dark-ground illuminators 44 



Adjustment of dark-ground illuminators 46 



Orthogonal illumination 50 



Differential color illumination 51 



Ultraviolet ray illumination 51 



Fluorescence microscope 52 



CHAPTER IV. 



ULTRAMICROSCOPES; APPARATUS FOR THE STUDY OF ULTRAMICROSCOPIC 

 PARTICLES. 



The principle of the ultramicroscope 54 



Brownian motion 55 



The diffraction images of ultramicroscopic particles 55 



The slit ultramicroscope and its adjustment 57 



Reflecting condenser ultramicroscopes 65 



The cardioid ultramicroscope 67 



The reflecting prism ultramicroscope of Cotton and Mouton 69 



The Jentzsch reflecting condenser 71 



The immersion ultramicroscope 72 



CHAPTER V. 



THE EXAMINATION OF OPAQUE OBJECTS; VERTICAL ILLUMINATORS; 

 METALLURGICAL MICROSCOPES. 



Simple vertical illuminators 76 



Adjustment of vertical illuminators 78 



Interpretation of appearances 80 



Special forms of vertical illuminators 81 



Maintaining the alignment of illuminator and radiant 87 



Mounting polished specimens for study 89 



Metallurgical microscopes, metallographs 90 



Shop or Works microscopes 99 



