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THE GUIDE TO NATURE 



earth. It therefore follows that when 

 the moon passes between the earth and 

 the sun and its shadow extends di- 

 rectly toward us that it is generally 

 not quite long enough to reach the 

 earth. When the moon happens to be 

 a little nearer to us than usual, how- 

 ever, almost the extreme tip of the 

 shadow may fall upon the earth and 

 so form a little round, dark area, which 

 is never more than 175 miles across. 

 This sweeps over the earth's surface,, 

 tracing a narrow strip across the lands 

 and seas, and all observers inside this 

 strip see the sun completely hidden. 



The eclipse of April 17 is a very pe- 

 culiar one. The produced shadow cone 

 first strikes the earth at A, Figure 

 3, at 5 hours 1 minute, A. M., and 



Figure 2. — Passage of the moon through the earth's 

 shadow on April 1st. 



sweeps over the Atlantic ocean along 

 the line ABCD. One hour and 18 

 minutes after the beginning it has 

 reached the point B, by which time 

 the moon has drawn enough nearer to 

 the earth's surface so that the shadow 

 cone itself actually reaches the earth, 

 and this continues while the shadow 

 is moving from B to C. Observers on 

 the path between B and C will there- 

 fore see a total eclipse ; that is, they 

 will see the sun entirely hidden, but 

 when the point C is passed the dis- 

 tance from the earth to the moon 

 again increases and the shadow no lon- 

 ger reaches the earth. 



By all observers along the narrow 

 path ABCD the center of the moon will 

 be seen to move exactly across the 

 center of the sun. Observers anywhere 



within the area MADN, north of this 

 path, will see the moon hide the lower 

 edge of the sun from view ; outside of 

 the area MRN the eclipse will be 

 wholly invisible. 



Residents of our country who live 

 along and to the east of the line KL, 

 which crosses Eastern New York and 

 Long Island, will see the eclipse begin 

 just as the sun is rising; those between 

 the lines KL and ME will see the sun 

 rise partially eclipsed, while to those 

 west of the line ME no part of the 

 eclipse will be visible. By the use of 

 a darkened glass the passage of the 

 moon over the lower edge of the sun 

 may be clearly witnessed, but from no 

 place in the United States will a very 

 large part of the sun's disc be hidden. 



THE PLANETS IN APRIL. 



The little planet Mercury passes to 

 the west of the sun and becomes a 

 morning star on April 15 at 7 A. M., 

 but it will not reach its greatest dis- 

 tance from the sun and so become 

 easily visible until the middle of May. 

 On the morning of April 28 this bright 

 little world will be found so near the 

 far more brilliant Venus that the two 

 objects will look like a double star in 

 the early morning dawn. The obser- 

 ver has perhaps noticed how brightly 

 the latter planet has been shining in 

 the morning sky and how it also has 

 been drawing so rapidly near to the sun 

 that as the days go by it is seen with 

 ever-increasing difficulty. On April 

 1 it rises 1 hour 10 minutes before 

 sunrise, while by April 30 this time is 

 shortened to only 40 minutes. On 

 April 28 it may be detected in the 

 dawn, a little way up from the east 

 point of the horizon, for a short while 

 before sunrise, and on this date the 

 planet Mercury will be seen lying to 

 the left of Venus at a distance away 

 from it only one-third as great as the 

 distance across the moon. 



The planet Mars will during the 

 month move from the middle of the 

 Milk}- Way to the center of the con- 

 stellation of the Twins. In a small 

 telescope this now appears but little 

 more than one-half full, so that it re- 

 sembles the moon when about two 



