724 



OPTIC PROJECTION 



Porte lumere, setting up 142 



for south window 143 



for west window 145 



Porter, T. C 424-426 



Position of Ballast 512-513 



condenser and objective. . .43, 251 

 of filament (mazda lamp) ... 91 

 of moving picture machine . . 396 



of object on stage 257 



of object with various ob- 

 jectives 256 



of switch 515-518 



Post-card projector 183 



Potato polarity indicator 511 



Potential drop and arc length 536-539 



and current 536 



and electrodes 536 



Potential, oscillogram, electro- 

 motive force supplied 494 



Potter, A. O 177 



Power at arc, wattmeter connec- 

 tions 482 



Power, Nicholas Company 



391,402,404,410,417 

 Power consumption, candle- 

 power 559, 561 



factor 485 



Precautions, alcohol lamp 133 



ammeter, wiring 481-482 



heavy currents 186, 513 



lime light 116 



in polarity tests 506 



for wiring 498, 513 



Precision Machine Co 406 



Presbyopia, old age sight. . . .661-662 



Pressure gauges 102, 103 



gauge, acetylene tank 128 



of one atmosphere 103 



reducing valve 102 



Prestolite tanks 127, 128, 129 



Principal axis 577~58i 



focus and how obtained . . 578-579 



Print, size for lantern slides 208 



Printing, artificial light 214 



on paper or a dry plate, 



directly 381 



exposure for 380 



how to hold paper 379 



lantern slides 209 



lantern slides with camera. . . 213 



paper to use 379 



Prints, enlarged from negatives. 378 



white on black 213 



Prism, 37, 46, 190, 196, 322, 337, 344, 

 368, 629-632, 640-643 



erecting 368 



direct vision 627, 631 



drawing 322, 337, 344 



glass 627, 629-630 



hollow for liquids. . .627, 631-632 



polarizing 622-626 



quartz for ultra-violet 641 



right-angled with vertical 



objective 46 



Rutherford's 630-631 



spectacles of 37 



Prism, Nicol for polarizing or 



analyzing light. . .622, 624, 626 

 Proceedings of the American 

 Association for the Ad- 

 vancement of Science ..211,321 

 Proceedings of the International 



Electrical Congress 566 



of the American Microscop- 

 ical Society 320 



of the Royal Society 426 



Projection apparatus, with mir- 

 ror on lecture table. . . .451-452 



outside the room 453 



for photographic enlarge- 

 ments 378 



rules for construction 6 



aid to drawing 319 



apparatus, best position in 



room 446 



early use with drawing. . . . 372 



form for drawing 321 



home-made 287 



similarity of all 221 



from three standpoints 3 



universal 178, 185, 191 



of human face 1 70 



horizontal objects 



33, 185, 190, 268 

 illumination in high power. . . 271 



in physics 621-651 



material and apparatus for 



622, 626-627, 643, 644, 651 



of spectra 626-642 



special experiments in 622 



with polarized light 622-626 



with ultra-violet light 



627, 641-642 



microscope, 178, 221, 222, 271, 

 282, 299, 300, 303, 309, 322, 598 

 60 1 

 microscope with amplifier 



238, 366, 599-600 



drawing with 333 



erect images with 367-373 



