722 



OPTIC PROJECTION 



Oculist's trial lenses, 651, 655 



where to be obtained 651 



Ohm 477, 521 



Ohmage 477 



Ohmage by Ohm's law 521-522 



Ohm's law 521 



Oil lamp 121 



Object, position on stage 257 



for projection, objectives. . . . 268 

 projection when horizontal. . 268 

 size for opaque projection ... 179 



visibility of 227 



to draw with projection 



microscope 333 



erect image when vertical. . . 190 



horizontal, image erect 190 



how to light 335 



illumination with main con- 

 denser 234 



large, drawing with low 



powers 333 



for opaque projections 1 79 



position with different ob- 

 jectives 256 



Objective 18, 224, 226, 281, 609 



aperture for opaque and 



transparent objects 172 



apparatus at rear of room . . . 464 

 apparatus not at rear of room 



464, 468 

 brilliancy of the screen image 613 



centering 247 



demonstrations with high 



powers 271 



diaphragm of 380 



distance from condenser 43, 247 



drawing 335 



focus and brightness of 



screen 613 



focus for room and screen . . 467 



for different sized fields 254 



formula for getting proper 



focus 467 



with hood for 245 



immersion 225, 349 



low power, mounting 241 



magic lantern 



18, 464, 597, 601, 609 

 microscope construction .... 616 

 microscope and image forma- 

 tion with 616 



moving picture 406 



painting black 246 



Objective, photographic, con- 

 struction 225 



for photography 384 



for photographic printing. . . 379 

 proportioned to condenser 43, 277 



revolving nose-piece for 249 



screen limited in size by 469 



shield for 30-31, 246, 293 



to use with substage condens- 

 er 281 



various fields 255 



various objects 268-269 



Old age sight or presbyopia 66 1 



Opaque lantern for drawing. . . . 332 

 drawing on horizontal surface 332 



one source 173 



two sources 173 



with sunlight 174 



Opaque objects, bright images of 174 



lighting entire 187 



magnification and size of 



image 181 



projection, 166, 168, 183, 184, 187, 

 188, 191, 192, 196 



screen and distance 181 



size and kind of objects 179 



summary 198 



troubles 195 



versus transparency. 1 68, 169, 170 

 Operating room, for moving pic- 

 tures 396-39 8 , 453 



construction (M. P. World) . . 397 



permanent 396 



temporary 396 



Operation of moving picture 



machine 420 



Operator, competent 390 



Optical bench 288-289, 294 



deceptions 36 



system for spectra 628, 641 



Optics of moving pictures. . .409, 591 



of projection, general 572 



Orange G for staining masks .... 253 

 Oscillogram, anode currents. . . . 495 

 current supplied and de- 

 livered 493 



potential and electromotive 



force 494 



rectifier 493~495 



Oxodium 113 



Oxone 113 



Oxygen, cylinder 101 



