POPULAR ASTRONOMY. 



363 



shows in addition to the cyanogen 

 hands found in all comets the bright 

 lines in the yellow part of the spectrum 

 due to luminous sodium vapor. This 

 constituent of common salt is very 

 seldom seen in a comet, and we recall 

 it in the Wells comet and the great 

 comet of 1882. It is probable that the 

 closeness of the comet's approach to 

 the sun caused the appearance of the 

 sodium lines. As a result, it shows 

 with a yellowish light. Comet A, 1910, 

 was but 4,000,000 miles from the sun 



like tails of hydrocarbons; and third, 

 short, stubby tails of metallic vapors. 



The Planets. 



Venus passed between the earth and 

 the sun oh February II, and is now a 

 morning star, rising before the sun. 

 On March 18 it attains its greatest 

 brillancy. Mars is gradually getting 

 fainter, and may be seen towards the 

 southwest in the early evening. About 

 March 10 it will be directly south of 



Evening SkyMap for March 



March Moon Phases, 

 last quarter. mar. 4 



NEW MOON, Mar. M. 

 FIRST QUARTER. Mar '7 

 FULL MOON, Mar. 25 



MAP FOR 



9?M.i 5 - T 



8PM 15* 

 7PM 5l s - T 



Columbia 



PLANETS -< 



IN THE 



EASTERN 

 MORNING 



'MARCH IIT 



when nearest it, and it moved at the 

 rate of 1,000,000 miles per hour! 



That its tail pointed directly away 

 from the sun was very evident.. A 

 comet's tail. how r ever, is also curved 

 in the direction away from its motion. 

 The curvature of their tails has been 

 carefully investigated by the Russian 

 astronomer Bredechin. who found 

 them to be three main types; first, 

 long straight tails, which he imagined 

 consisted of hydrogen ; second, plume- 



the Pleiades. On the first of the month 

 Jupiter rises shortly after eight o'clock. 

 It is at apposition March 30, and so is 

 on the meridian due south on that date 

 at midnight. It is then nearest the 

 earth and consequently brightest. It 

 will therefore be a magnificent object 

 all this month. Saturn is seen low 

 down towards the southwest in the 

 early evening. 



Spring begins March 21 at 7 : °3 

 A. M. Eastern Standard time. 



