730 OPTIC PROJECTION
Ultra-violet, quartz optical sys¬
tem for.............641-642
radiation..........567,641-642
projection of...........640- 642
United States Geological Survey 147
Units of alternating current. 484-486
Units of direct current......475-483
Units of electricity.........475. 484
University of Pennsylvania and
animal movement ....... 6S2
Unpacking moving picture ma¬
chine................... 401
Uranium arc for spectra........ 628
when in the positive, and
when in the negative elec¬
trode................... 640
Valspar varnish for water cells
2°5, 264
Varnishing lantern slides....... 205
Vertical microscope for high
powers................. 283
Vertical knife switch.......... 516
Vertical projection............ 33
Violet lines in arc stream....... 546
Visibility of objects........... 227
Vision, daylight and twilight
121, 175. 444
Vision, experiments with normal
651-659
defective..............659-672
persist nee of in moving pic¬
tures ..................
Visual angle.................. 228
Voigtländer und Sohn......226, 250
Volt and voltage...........476, 484
Voltage, alternating current. .. . 484
by Ohm’s law............. 521
intermediate.............. 544
of line anti arc............. 544
of line, voltmeter connections 475
not present in the line....... 46
Voltmeter, connection for arc
voltage ................ 476
connection to circuit........ 478
direct current.............. 478
for line voltage............ 475
for polarity testing......... 508
soft cored................. 510
Walgensten.............3, 675-677
Wall diagrams.............329, 355
Wall receptacle.............86, 503
Water-cell, 13, 15, 18, 57, 63, 71, 161,
194, 222-223, 237, 239-240,
264-266, 276-277, 281-282,
287. 299, 301, 309, 355. 365.
421, 432, 571, 592, 604-609
absorption of radiant heat not
affected by temperature... 606
effect of alum, etc. in....... 607
efficiency..............568-569
light and energy absorbed by
604-607
in micro-projection......... 237
the microscope stage in.....608
how to make..... ......... 264
need in moving pictures. .421,432
with ordinary microscope*. . . 266
position in micro-projec¬
tion.................239. 240
shadow from.............. 57
stage .................239-240
sunlight.................. 161
sun and micro-projection.... 287
with two-lens condenser. .365,421
Water cooled rheostat......... 527
Waterhouse, Gen. J........... 673
Watt, and wattmeter.477, 482-483
Watts, alternating current..... 485
equal volts times amperes
477.521
Wattmeter................482-483
amperage by.............. 483
connecting ............. 482
power at arc by............ 482
power from dvnamo........ 483
White, Dr. A. C.'.............. 673
White-washed wall screen...... 455
Wiedemann’s Annalen...... 647
Williams, Brown & Karle
59, 91, 107,130, 131, 182, 183, 300
Wimmer....................9. 202
Winding and rewinding moving
picture film............. 430
Widow in lamp-house
72,267,402-403
Window shades for darkening
the room............445-447
Wires for the electric circuit. 496-505
how to connect............ 503
insulation of...........497-498
wrong polarity......51, 506-511
Wiring the are lamp, 10, 13, 15. 71 •
84, 263, 324, 339-340. 399,496-
535, 639