NORTHERN LIGHTS— EVE 147 



This experiment is better shown by projecting the electrons through 

 a small hole so that they glance along a fluorescent screen. It is then 

 easily seen that the beam of electrons is readily bent into a circular 

 arc on the approach of a magnet. 



Two streams of electrons, passing through neighboring holes, may 

 be seen to repel one another, whereas parallel currents in the same 

 directions, passing along wires, are known to attract. All these 

 preliminary remarks have a direct bearing on the main theme — 

 Northern Lights. 



THE UPPER AIR 



Dwellers in cities see little of the night sky; they are dazzled by 

 street lights and advertising signs. Those who live in the country 

 enjoy a greater privilege. Although London is nearer to the North 

 Pole than Montreal or Quebec, yet it is the people of Canada who more 

 frequently see the glory of the Northern Lights. It is the distance 

 from the magnetic axis of the earth that counts, and that axis meets 

 the earth about midway between the north magnetic pole and the 

 North Pole. This might be called the north axial pole, and it is near 

 northwestern Greenland. 



Tlie appearance of the Northern Lights has been frequently de- 

 scribed, and in any case words are quite inadequate to describe its 

 beauty. We must look forward to the time when really good colored 

 motion pictures of the aurora have been taken, and this will be a diffi- 

 cult feat because the light intensity is feeble compared with sunlight. 

 The three main forms of display are the arc or arch, the curtains, and 

 the long streamers. The color is commonly greenish white or greenish 

 yellow, sometimes with an admixture of red or violet. I still remember 

 being taken as a small boy from bed at my home in the Midlands to 

 see from a window the rosy glow of the Northern Lights. It was the 

 winter of 1870-71 when the Prussians were besieging Paris, and the 

 villagers declared that the light was the reflection of Paris on fire, 

 regardless of the fact that Paris was to the south and the lights to the 

 north. 



The first appearance of the aurora is sometimes a bright quiescent 

 arch with its peak a few degrees west of due north. This may sud- 

 denly be followed with a host of streamers, like searchlights, but 

 changing, flickering, and dancing. This is rather frivolous behavior, 

 for the Eskimo believe that the lights are the spirits of their ancestors. 

 At other times the display begins with nearly vertical curtains of 

 light, the folds of which keep changing in form. It is often a fascinat- 

 ing and resplendent spectacle, and it is pardonable if a word picture 

 falls short of the reality. The drapery is usually to the north, spread- 

 ing from east to west, but sometimes it appears quite overhead. Even 



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