Eyepiece or Ocular, Defects in, 112 



English Type, 107 



Erecting, 110 



How to Attach, 116 



Huyghenian, 107 



Index, 111 



Kellner, 109 



Micrometer, 109, 110, 178, 181 



' Negative, 107 



Orthoscopic, 109 



Parfocal, 106 



Periscopic, 109 



Projection, 109, 112 



Rams den, 109 



Rating of, 104 



Searcher, 111 



Selection of, 189 



Solid, 108 



Eyepiece Micrometer, 179, 193 



Eyepoint, 132, 105, 106 



Field of View, 16, 17, 95, 101, 104 



Field, Flatness of, 95 



Field-lens, 58, 107 



Filar Micrometer, 180 



Finding the Object, 118 



Fine Adjustment, 32, 48, 186 



Care of, 198 



Focusing with, 128 



Fixed Mechanical Stage, 41, 188 



Flatness of Field, 95 



Flint Glass in Achromatic Combination, 13 



Focal Length, 5 



To Determine, 6 



Focal Point, 5 



Of Mirror, 53, 122 



Focus, Equivalent, 62 



