INDEX 



315 



lantern slides, 245 ; enamel for 

 glazing. 242 



Colonies of bacteria, 270, 271 

 Colour-contrast, 205 : to increase, 216, 



289, 292 ; to reduce, 217, 288 

 Colour-fringes, 30 ; as test of ocular, 42 

 Colour-screens, uses of, 205 ; spectra 



of, 210-214 



green, 210, 211, 292, 294, 302, 

 Zettnow's. 212, for dark-room, 

 199; yellow, 180, 211, 227; 

 yellow-green, 210, 212, 228, 

 288; blue, 213, 215 

 permanent, gelatin, 200, collodion, 

 207 ; fluid, cells for, impro- 

 vised, 208, Zeiss, 208. Kings- 

 ford's trough, 209 ; glass, 210, 

 didymium, 218 



as depending on illuminant, 213, 

 294, with mercury-vapour 

 lamp, 92, 214 ; as affecting 

 exposure, 227 ; to increase 

 colour-contrast, 205, 216, 289, 

 292, to reduce, 217 ; use with 

 achromatic objectives, 153 ; 

 when focussing, 191 ; with 

 gelatin dry-plates, 219; in 

 metallurgical work, 267 ; for 

 coloured lantern-slides, 277, 

 280-282 



Coloured lantern-slides, vide Lantern- 

 slides 



Condensers, vide Sub-stage Condensers 

 Cone of light, 23, 25 ; solid or hollow, 

 48 ; aplanatic, 47-49 ; size of, 51, 

 162, 166, 167, 292, 295 

 Continental model microscope, 7, 161 

 Continental tube-length, 40, 151 

 Copying diagrams, 270 

 Correction, for chromatic aberration, 

 21, 29, 30, 300 ; for spherical aber- 

 ration, 21, 29, 30, 47, 48 ; for cover- 

 glass thickness, 154-160 

 Correction-collar on objective, 33, 155; 



adjustment of, 156-158 

 Cover-glass thickness, effect of, 154 ; 

 correction for, by correction-collar, 

 56, 155, by alteration of tube-length, 

 155 ; use' of Abbe test-plate, 29. of 

 Podura scale, 158, of diatom, 159 ; 

 measurement of, approximate, 156, 

 more exact, 157 



by Zeiss paraboloidal condenser, 

 57 ; by Leitz dark-ground conden- 

 ser, 59; J. W. Gordon's method, 

 59 ; resolving power with, 60 ; with 

 vertical camera, 117; for instan- 

 taneous photo. 140 



Dark-room, equipment of, 201-204 ; 

 illumination and lamps for, 198- 

 200 ; temperature of, 201, 230 



Dark-slide, 183; in testing dark- 

 room light, 201 ; in stereoscopic 

 work, 274 



Davis diaphragm, 286 



Drives, J., 310 



D?pth of focri, vide Penetration 



Desch, Dr. C. H., on metallography, 

 265 



Developing, 229 ; factorial method, 



I 230; solutions for, 229, 231, 



T particular cases, 287, 289, 292, 293, 

 295 ; for over-exposed plates, 232, 

 233, for under-exposed, 233-235 ; 

 of prints, 240 ; for lantern-slides, 

 dry-plate, 243, wet-collodion, 247 ; 

 for coloured lantern-slides, 278 



Diaphragms between camera front 

 and focussing- screen. 180 ; between 

 nrcroscope and light, 181 



Diatoms, mounting of, 24 ; as tests 

 for objectives, 28, 29, 159 ; reso- 

 lution of structure, 156, 161, 216 ; 

 illumination of, 60, 293, 295, 302, 

 303 ; annular illumination of, 167 ; 

 measurements of, 198 ; colour- 

 screens for, 211 ; examples, 290, 

 Amphipleura pellucid a, 29, 301, 

 303, Navicula lyra, 294, 300, 

 Orthonies splendida, 292, Pleuro- 

 figma angulatum, 28, 159, 301 



Didymium glass, 218 



Diffraction, fringes. 24, 51, 290, 293, 

 295, 297 ; scattering of light, 222 



Diffused light, 68, 179 



Dishes, porcelain, 203 



Draining rack, 203 



Dry lenses, vide Objectives, dry 



Dry-plates, 218 ; for lantern-slides, 

 242-244 ; storage of, 204 



Drying rack, 203 



Dufay plate for coloured lantern-slides, 

 277, 280-282 



Dust, on ocular, 153 ; shown by 

 negative, 233 



D.P.H., microscope stand, 14 



Dark-ground illumination, 28, 53, 56 ; 



by spot-lens, 53 ; by paraboloid, 



54 ; by stop in sub-stage condenser, 



54, 287 ; by stop in objective, 56 ; 



ECHINUS, spine of, 28. 287 

 Edward's isochromatic plates, 220, 



291,292; Imperial, 287 

 Electric arc, vide Arc 



