Jy CONTENTS. 



TESTING OBJECTIVES. 



General Rules; Accepted Standards-Diatoms, Ruled Lines, Arti- 

 ficial Star; Podura; Nobert's Lines; Hollers Probe Platte; Table 

 of Diatoms on Holler's Probe Platte, with the Number of Lines 

 to the Inch on the Several Diatoms ; Hethods of Testing for Flat- 

 ness of Field, Penetration, etc., - - - . - 84 



SELECTION OF A MICBOSCOPE FOK PRACTICAL PURPOSES. 

 Hust be Adapted to Reauirements and Skill of User; Hlcroscopes 

 for Botany ; For Physicians ; For Students ; Magnifying Power 

 Required ; The Stand ; The Stage ; Mechanical Stages ; Revolving 

 Stage ; Stages for Special Purposes ; Diatom Stage, Safety Stage, 

 etc.; Sub-Stage; Mirror; Body; Draw-Tube; Adjustments for 

 Focussing; The Diaphragm; Objectives; High versus Low 

 Angles; Eye-Pieces. - - -, - - '-' - M 



ACCEBSOBI APPARATUS. 



Stage Forceps; Forceps Carrier; Object Holder ; Plain Slides; 

 Concave Slides ; Watch-Glasses ; Watch -Glass Holder', Animal- 

 cule Cage ; Large Zoophyte Trough Small Zoophyte Trough ; 

 Walmsley's Zoophyte Trough; The Weber Slide; The Cell- 

 Trough ; The Compressorium > Gravity Compressoriuni ; Grow- 

 ing Slides; Frog Plate; Table; Double Nose-piece, - - 12; 



ILLUMINATION SOUBCES OF LIGHT. 



Sun-Light; Artificial Light Candles, Gas, Lamps, Magnesium. 

 Oxyhydrogen Light ; Parallel, Convergent and Divergent Rays, 143 



ILLUMINATION OF OPAQUE OBJECTS. 



Diffused Light; Bulls-Eye Condenser; Side Reflector: The Lieber- 

 kuhn; The Parabolic Reflector ; Objectives with Tapered Fronts; 

 Smith's Vertical Illuminator ; Tolles' Vertical Illuminator. - 147 



ILLUMINATION OF TRANSPARENT OBJECTS. 



Direct and Reflected Light; Axial or Central Light; Oblique 

 Light : The Achromatic Condenser ; The Webster Condenser, and 

 How to Use it; Wenham's Reflex Illuminator, and How to Use 

 it; The Wenham Prism ; The Hemispherical Illuminator; The 

 " Half Button " ; The Woodward Illuminator; Tolles' Illumina- 

 ting Traverse Lens ; The Spot Lens ; The Parabolic Illumina- 

 tor; Polarized Light, - - - .... 150 



How TO USE THE MICROSCOPE. 



General Rules ; Simple Hand Magnifiers : Compound Microscopes ; 

 Practical Notes on Illumination; White Cloud Illumination; 

 Monochromatic Light ; Blue Cell ; Opaque Objects ; Hints to Be- 

 ginners. --. 164 



How TO USE OBJECTIVES OF LARGE APERTURE. 

 Illuminnttion; Collar-Corrosion for Cover-Glass, - - - m 



