

THE GUIDE T< ) N VIVUK 



Evening Sky Map for November. 



BY PROF. .\ I.IK III > MITCH 111. I.. OF COLUMBIA 

 1 MVKRSITY. 



During November, there are two 

 eclipses, one of the sun. and one of the 

 moon; the first cannot he seen any- 

 where in the United States, while the 

 second will he fairly well visible. On 

 the second day of the month an unin- 

 teresting - partial eclipse of the sun oc- 

 curs in the North Pacific Ocean. A 

 half month later, on the sixteenth, a 

 total eclipse of the moon takes place, 

 which will he visible in all its phases 

 to the residents along the eastern coast 

 of the United States and Canada. For 

 localities half way across the conti- 

 nent, part of the eclipse will happen 

 before sunset, while the sun is still 

 above the horizon and the moon below 

 it, and consequently invisible. On the 

 Pacific slope, the eclipse will end about 

 the time of moonrise. 



At the time of an eclipse, we realize 

 that the earth and moon both cast 

 shadows. Ordinarily we are not aware 

 that a shadow exists until it falls on 

 something. When the moon passes 

 into the shadow cast by the earth, we 

 have an eclipse of the moon, which is 

 total or partial, depending on whether 

 the moon is wholly immersed or not. 

 When the earth passes into the shadow 

 of the moon, there is an eclipse of the 

 sun. 



If one, however, would only take the 

 trouble to look, he could see the 

 shadow of the earth each clear day, 

 without having to wait for an eclipse. 



How many of us have looked to- 

 wards the east while the sun is setting, 

 to see what was happening there? We 

 are all of us very familiar with the sun- 

 set colors and the glory of the depart- 

 ing day by looking towards the w^est. 



The next clear day you experience turn 

 your back on the west and face the 

 east, and sec if you cannot find some- 

 thing there almost as interesting. The 

 earth must cast a shadow, and if this 

 shadow falls on any solid bodies, we 

 will become aware of it? How, then, 

 about the solid particles in our atmo- 

 sphere, the dust specks? We can see 

 these when a ray of sunlight shines 

 across a darkened room. The dust is 

 carried many miles up into the atmo- 

 sphere, and the beam of the electric 

 searchlight across the night sky makes 

 it plainly visible. The dust is generally 

 least after a heavy rain. If it were not 

 for the dust and water vapor in the 

 atmosphere, darkness would settle 

 down on the earth very quickly after 

 sunset, twilight would be very short. 

 Twilight is caused by the reflection of 

 the sun's light from the solid particles 

 of our atmosphere, and is ordinarily 

 supposed to be lost until the sun has 

 sunk eighteen degrees below the hori- 

 zon. And if the sunset colors and twi- 

 light arc make the dust in the atmo- 

 sphere visible, why cannot we see the 

 earth's shadow? We can see it, if we 

 only try and observe it. On a clear 

 evening shortly after sunset one can 

 see the colors of gold and pink also in 

 the east. As the minutes pass, these 

 colors gradually fade and are pushed 

 up from the horizon by a bluish gray 

 darkness. If one has a good view of 

 the eastern horizon, he will see this 

 grayish color gradually rising up from 

 the horizon in the form of an arc of a 

 circle. As the time goes by, this arc 

 mounts higher and higher. The high- 

 est point of this arc is exactly opposite 

 the point wdiere the sun sets. This is 

 the shadow of the earth on the sky 

 which appears as the shadow bow. By 



