1. ELECTRICAL LIGHTING

2. Outline
Early Developments
Arc-Light
Incandescent Filament Lamp

3. Early Developments Incandescent Metallic Filaments de la Rue (1820)
Short Life In Air - Oxidation
Oxygen-Free Environment
de la Rue (1820)
Partial Vacuum
Platinum - Melt & Glow At Close Temperatures

4. Early Developments (Continued)
Previously
Coal Gas
Wax Candles
Fish-Tail
W. E. Staite (Mid 1840s)
Platino-Iridium Alloy Filament
Disintigrated
Lecture 1847
Joseph Swan Was In Audience

5. Arc-Light Staite (1847) Carbon Arc Automatic Feed
“Pyrometric Principle”
Heat Increases As Arc Lengthens
Carbon Consumed
Heat Generated
Carbon Wire Expands
Allowed Rack To Move
Raised Carbon Electrode
Shown
Limited By Daniell Cells Of Time
No Financial Backing

6. Arc-Light (Continued)
Foucault (1850)
Serrin (1857)

7. Arc-Light (Continued)
Duboscq (1858)
Regulator
Used In Lighthouse By Holmes
Steady Voltage
Controlled Advance Of Electrode

8. Arc-Light (Continued)
Crompton (1881)
Indirect Lighting
Bulb

9. Arc-Light (Continued)
Jablochkoff (1876)
“Electric Candle”
Parallel Carbon Electrodes
4 mm Diameter
Used AC