. The semi-centennial anniversary of the National Academy of Sciences, 1863-1913 . -y«--**-?» !? i*»^?^ ^^^ ^s*s^-v^ Fig. 6. Same Region of the Sun, ShowingTHE Hydrogen (Ha) Flocculi. THE SEMI-CENTENNIAL ANNIVERSARY 43 sun, glows like the hydrogen in this tube. Nitrogen, which ischaracteristic of a lower level, shines with the light which canbe duplicated here. But it may be remarked that this explanation of the aurora isonly hypothetical, in the absence of direct evidence of the emis-sion of electrons by the sun. However, we do know that hotbodies emit electrons. Here is a carbon filament
. The semi-centennial anniversary of the National Academy of Sciences, 1863-1913 . -y«--**-?» !? i*»^?^ ^^^ ^s*s^-v^ Fig. 6. Same Region of the Sun, ShowingTHE Hydrogen (Ha) Flocculi. THE SEMI-CENTENNIAL ANNIVERSARY 43 sun, glows like the hydrogen in this tube. Nitrogen, which ischaracteristic of a lower level, shines with the light which canbe duplicated here. But it may be remarked that this explanation of the aurora isonly hypothetical, in the absence of direct evidence of the emis-sion of electrons by the sun. However, we do know that hotbodies emit electrons. Here is a carbon filament in an exhaustedbulb. When heated white hot, a stream of electrons passes upon this electrode, the electrons discharge the electro-scope with which it is connected. Everyone who has to discardold incandescent lamps is familiar with the result of this blackening of the bulbs is due to finely divided carboncarried away by the electrons, and deposited upon the glass. Now we know that great quantities of carbon in a vaporousstate exist in the sun, and
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectscience, bookyear1913
