726 



OPTIC PROJECTION 



Reinhold, use of camera obscura 



in eclipses 674 



Requirements for good projec- 

 tion 



7, 18, 222-223, 313-317, 433 

 for projection with weak 



lights 120 



Resistance, to control current . . . 539 

 how to get amount needed ... 521 



unit of 477 



Retouching frame 29, 203 



Rewinding moving picture film . . 430 



Reynolds 374 



Rheostat 521-531 



adjustable 263, 326, 523-524 



alternating current 69, 532 



barrel, saltwater 525-526 



calibration of 525 



direct current 1 1 , 521 



energy used 533 



fixed 523 



heat developed in 523 



home-made 526-530 



installing 84, 339, 504, 524 



in parallel 531 



on 1 10 volt line 542 



range of 263, 326, 523-524 



salt water 525-526 



series 531 



tin strips 5 2 9-53 



water cooled 527-528 



wiring 504, 524 



Richardson's Motion Picture 

 Handbook . *..i ^ 



390-391,397,420,439 



Riley, Dr.. 327, 331 



Ripolin white paint 264 



Roaring of alcohol lamp 134 



Roaring of lime light 115 



Rods for optical bench 290 



Roller screens 456 



Rooms, for projection 439 



Room, apparatus on lecture table 



451-452 



darkening 443 



darkness for opaque projec- 

 tion 175 



for drawing and photography 321 



for micro-projection 235 



for moving pictures 395 



form for projection 440 



light in projection 441, 443 



limiting size of screen 469 



Room, size with sunlight 162 



tint and decoration 440 



troubles with 471 



Salt and water polarity indicator 511 

 water rheostat 525-526 



Scale, diagrams with opaque lan- 

 tern 356 



wall diagrams 355 



Scheiner 361 , 679 



demonstration of retinal 



image 656 



theory of accommodation 658 



Oculus 368 



Science 2 1 1 , 327 



Scientific American 221 



Schmidt & Haensch 102, 126 



Screens 454-466 



anthracene 627, 635-642 



Screen, in alcove 443 



cloth 457 



dark spots on 309 



distance 464-47 1 



distance, for high powers. ... 282 

 distance, micro-projection 



225,282 

 for opaque projection. . . 181, 454 



for high powers 272, 282 



hinged to meet axial ray 449 



image, actual size 257 



with amplifiers and oculars 258 

 perfection and brilliancy 



18,612-617 

 image, not photographically 



sharp 256 



with polarized light 626 



size of 464 



spectra 627, 635, 642 



stereoscopic 37 



with vision experiments 654 



not light enough 301 



with metallic surface. . . .458-463 



micro-projection 235, 454 



moving pictures 395, 454 



painted cloth 455 



painted on wall 454 



paper 45$ 



plaster of Paris 454 



qualities of goods. . . 454 



reflection 460-465 



reflection, semi-diffuse 459 



reflection, white . . 246, 460, 462 



