INDEX 



30"; 



Dark field, with Louchtbild con- 

 denser, 254 



with water-immersion, 208 

 Darwin, simple magnifier, 197 

 Datura stramonium, quadrivalents, 



224 

 Daylight glass, 76 

 Definition, losses in, 1 

 Dendrocoelum, chromosomes, 238 

 Denham, variable resistance, 78 

 Detto slide bar, 50, 139, 206 

 Diaphragm, drawtube, 262 



pivoted, 154 



source of light, 3 

 Diaphragms for twin objectives, 43 

 Diatoms, resolution of, 261 

 Diplopia, from unadjusted binoc- 

 ular, 24 

 Dippel, book on the microscope, 211 

 Discovery, methods of, 214 

 Dissection, magnifiers for, 105 



under water, 105 

 Doublet, defined, 14 

 Drawing, with camera, 161 



half-tone, 163 



India-ink, 163 



for lantern slides, 163 



magnification of, 164 



from photographs, 163 



practical points, 164 



reference letters, 163 



for zinc etchings, 163 

 Drawtube, care of, 181 



correction by, 142 



diaphragm in, 143, 262 



practical points, 145 



rackwork on, 56, 143 



routine work, 56 



summary, 145 



use of, 142 

 Drosophila, chromosomes, 238 



mutants, 240 

 Dust in the microscope, 182 



E 



Eastman Kodak Co., Wratten films, 

 75 



Ehringhaus, booklet on the micro- 

 scope, 209 



Embryo chick, 239 

 Enlargement, 101 

 Epidermis, origin of, 231 

 Errors, accumulation of, 1 



in microscopy, 6, 190 



in photography, 165 

 Eye, unoccupied, 15 



with monocular, 55 

 Eyepiece, boundary of field, 150 



caps, with glasses, 24, 25 



care of, 182 



changing, 57 



circles, 30 



magnifying, 263 

 and pupil, 31 



compensating, 147 

 origin of, 200 

 use of, 148 



constant, 151 



changing, 149 



diaphragm, 151 



eyepoint of, 147 



Huyghenian, 147, 150 



kinds of, 147 



low and high, 35 



magnification, 120, 149 



measuring, 151 



optimum use of, 148 



orthoscopic, 147 



parfocal, 40, 150 



periplane, etc., 147 



photographic, 148 



practical points, 152 



projection, 166 



pulling out, 113 



summary, 152 



testing, 172 

 Eyepoint, 30, 147, 150 

 Eyes, blind spots of, 50 



floating fibers in, 50 



F 



Ferns, fertilization of, 232 



Field of view, 18, 28 



Filaria, smear, 239 



Filters, yellow-green, transmission 



of, 78 

 Fine motion, care of, 182 

 use of, 2 



