466 



GENERAL SCIENCE 



the weather. The direction in which the cusps of the moon point 

 depends upon the position of the sun, since the horns must point 

 away from the sun. On the moon there is no twilight because 

 there is no air. The sky is black and covered with stars, even at 

 midday. There are no gorgeous colors of the heavens at sunrise 

 or sunset, for the sun rises instantly into day, and after two of our 

 weeks goes down. Night falls at once. 



The Man in the Moon. The moon appears to be dotted here 



and there with great volcanic 

 craters and mountains. When the 

 sun strikes one of these mountains 

 obliquely a shadow is distinctly 

 seen, causing the appearance of 

 the "Man in the moon" or the 

 "Lady in the moon." All these 

 craters and mountains have been 

 named after distinguished men 

 in science. Copernicus is the 

 largest volcanic crater. It is 

 situated on the top of the nose 

 of the man in the moon. Its 

 diameter is 46 miles. 



Tides. Twice a day, about 12 hours and 25 minutes apart, the 

 water of the ocean begins to move toward the shore. This motion 

 continues for about 6 hours, and is called flood tide. For the next 

 6 hours the water flows back in the motion known as* ebb tide. The 

 tides are caused by the moon pulling the water on the surface of 

 the earth. Since the water is free to move, it follows the sun and 

 the moon about, as the earth rotates on its axis. If the sun and the 

 moon are on the same side of the earth, we have very high tides 

 on the side of the earth toward the sun and the moon and on the 

 side of the earth directly opposite, since the sun and moon are 

 pulling the water away from the earth. If the sun and moon are 

 on opposite sides of the earth we also have very high tides. When 

 the sun and moon are on the same side, it is said that they are in 

 conjunction; on opposite sides, in opposition. When the sun and 

 moon are in conjunction or opposition, the tides are called spring 



FIG. 355. Eclipse of the moon. 



