Crown Glass in Achromatic Combination, 13 



Defects in Eyepieces and Objectives, 112 



Diameters Magnification, 24 



Diaphragm, 10, 33, 129 



Cap, 54 



Eyepiece, 107 



Iris, 54, 157, 158 



Revolving, 53 



Substage, 53, 129, 157, 158 



Use of, 129, 163 



Diatoms as Test Objects, 133 



Dispersion of Light by Prism, 11 



Dissecting Microscopes, 18 21, 193 



How to Use, 21 



Double Nose-piece, 43, 118 



To Focus with, 127 



Double System of Lenses, 66 



Doublet Magnifier, 15 



Draw-Tube, 31, 49 



To Operate, 50, 114 



Drawing Objects with Camera Lucida, 167 



Drawing Table, 174, 175 



Dry Adjustable Objectives, 143 



Dry Objectives, 60, 75 



English Type Eyepiece, 107 



Erecting Eyepiece, 110 



Equivalent Focus, 62 



Excelsior Dissecting "Microscope, 20 



Eye, Which to Use, 21, 131 



Eye-lens, 58, 107 



Eyepiece or Ocular, 31, 55, 107110, 189 



Binocular, 110 



Care of, 200 



Compensating, 103, 111 



Continental Type, 107 



