KNOWLEDGE 



[Janiaby, 1902. 



liare," is very near the point of an equilateral triangle, 

 of wliich Beta and Kappa Orionis fomi tlio base. 



A far more majestic triangle, and more nearly exact 

 in its proportions, is that formed by Betelgeuse, Sirius 

 and Procyon. 



" Let I'roovon join with Betoljieusc ami pass a. line afar. 

 To reacli the point where Sirius glows, the most con- 

 spicuous star ; 

 Then will the eye delighted view a figure fine and vast; 

 Its span is equilateral, triangular its cast. 

 Tho constellation of Canis Major, though in itself a 

 brilliant one, lies so low for English observers that 

 practically we think of little but its chief star. But 

 this is so far and away the brightest in the sky, being 

 more than two full magnitudes brighter than the average 

 first magnitude star, such as Aklobaran or Alt<air, and 

 is rendered so unusually striking by the intensity of its 

 scintillations, that it serves alone to amply distinguish 

 tho constellation to which it belongs. Its excessive 



or " prince," or " the bright and thining one " ; all 

 equally natural and appropriate for this prince of stars. 

 Our name for the Lesser Dog, Procyon, is simple enough. 

 It is merely " before tho dog "; in other words, Procyon 

 was tlio forerunner of Sirius, not as crossing the meridian 

 earlier, but as rising before it and so heralding its 

 appearance. 



The colours of the four brightest stars of this region 

 are very well worth studying; the orange of Betelgeuse 

 being in strong contrast with the steel-blue of Rigel and 

 Sirius, whilst Procyon, though a white star, yet shows a 

 distinct creamy or yellowish tinge, which to a sensitive 

 eye is on a fine night very clearly distinguishable from 

 the colder hue of the two brilliants first named. 



The constellation of tlic Lesser Dog in Ptolemy's 

 Catalogue numbei-s only one star in addition to Procyon. 

 This is Beta, Gamcisa, the " dim-eyed," possibly as mean- 

 ing that Procyon is so much less brilliant than Sirius. 



IX 



VIII 



Vil 



VI 



IV 



J..- «„ , ••* CANCER 'P ! ^,^^^„ •fi 

 LEO '.'-■■'■•*-' ^ •.'a /CANIS MINOR 



e,3 \>^- A^. ORION '"'[''r "^'^''^^ 



,•47 



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/•., ANTLIA ; 

 i 



i ■ /' '^ «. 



ARGO VELA-".c" .' 



"3 *v«l'' r PUPis 



••X C EN TAURUS . 

 W 



CARINA 





PICTOR y "c DORADO 'y 



XII XI X IX Vlil VII VI V IV 



Star Map No. 12; The Great Hunter and his Dogs. 



scintillation is due to two causes ; the one that in these 



latitudes it can never attain any great elevation ; the 



other, its striking blui.'^h-white colour. For stars of that 



colour scintillate more markedly than those of any otl-.cr, 



and Sirius being the very type and model of the class, 



its flashing rendcre it as conspicuous as its brightness. 



" The fiery Sirius alters hue. 



And bickers into red and emerald." 



The name Sirius is usually taken as bearing its Greek 



meaning of " sparkling," " burning, ' or " scorching," an 



appropriate enough name for the brightest of the stars 



and one in conjunction with the sun at the beginning 



of summer. Other renderings intei^pi-et it as " chief," 



Or it may be that it is a corruption of Al Gamus. tho 

 " puppy." A glance at the sky shows that Procyon and 

 Gameisa stand at much the same distance apart as Castor 

 and Pollux, and tho Arabian astronomers tised to call 

 tho space between the two stars of the Twins " the long 

 cubit," whilst that between the two' of the Lesser Dog 

 was " the short cubit, ' — an old instance of the tendency, 

 which seems so irresistible, to accouat a space in the 

 heavens of some seven to ten degi'ees of aix in length 

 as equivalent to a teiTcstrial yard. 



Procyon and its companion form yet another proof 

 that the constellation names were not given in conse- 

 quence of forms suggested by the actual groupings of 



