536 SCIENTIFIC RECREATIONS. 



Herschel, to a particular place in the constellation called Hercules. There 

 are now star catalogues and star maps, for the heavens have been as closely 

 surveyed as the earth, and by accurate observations it has now become 

 possible to find the position of every star usually visible. Some of the stars 

 are used as " clock " stars, by which sidereal time can be calculated 

 accurately, and the clocks thereby corrected. The stars, though termed 

 " fixed," are in perpetual movement Arcturus at the rate of fifty miles a 

 second, and others less. Only the rates of a few are known. 



The number of the stars is beyond our calculation, and even the 

 number of stars only visible in the telescope amount to millions, and these 

 are called telescopic stars. The visible stars amount to about six thousand, 

 and of course these are the brightest up to the sixth magnitude. There are 

 more visible in the southern than in the northern hemisphere. The magni- 

 tudes of the stars range in classes according to the brightness of the stars 

 observed, for this is really the test from the first magnitude to the sixth ; after 

 that the telescopic stars are seen up to the fifteenth or sixteenth. We 

 can only see about three thousand stars at any one time from any place, 

 although, as remarked above, many millions may be observed with a good 

 telescope, and as many more, probably twenty millions, are invisible. 



We will now proceed to detail the constellations, which are familiar by 

 name to everybody. We have already given the names of the zodiacal 

 groups, which consist of many stars, each designated by a letter of the Greek 

 alphabet so far as possible, then the Roman letters and numerals are 

 employed. Thus a (Alpha) is the most brilliant star ; /3 (Beta) the next 

 bright 7 (Gamma) the next, and so on ; so the relative brilliancy of the 

 stars in the constellation is indicated, but not the very biggest star of the 

 first magnitude is intended by a, for the star B in one constellation may 

 equal a in another. John Bayer originated this method in 1603. 



The arrangement of the constellations is plunged in the obscurity of 

 ages, but B.C. 370 there were forty-five thus grouped. There are northern 

 and southern constellations which are visible above our old friends Aries, 



Taurus, Cancer, etc. We will, as in 

 duty bound, consider our old acquaintances 

 first, and then give a list of the north- 

 ern and southern groups of stars ; but we 

 shall find that the forms are in the greater 

 part due to the imagination of the ancients, 

 and do not bear out our ideas of the animals 

 they are supposed to represent, while at the 

 same time they cross and recross with other 

 constellations in the skies in a very puzzling 

 way. 



The first constellation is ARIES, the 

 Ram, which is celebrated in mythology as 

 the proud possessor of the Golden Fleece, which we may remember was 



