CHAPTERS ON THE STARS. 315 



the plates are exposed for five minutes, will all correspond, and that 

 the smallest stars found on the plates will be of the eleventh magnitude. 



In the case of the lucid stars this difficulty does not arise, because 

 the photometric estimates are on a sufficiently exact and uniform 

 scale to enable us to make a count, which shall be nearly correct, of all 

 the stars down to, say, magnitude 6.0 or some limit not differing 

 greatly from this. Several studies of the distribution of these stars 

 have been made; one by Gould in the Uranometria Argentina, one by 

 Schiaparelli, and another by Pickering. The counts of Gould and 

 Schiaparelli, having special reference to the Milky Way, are best 

 adapted to our purpose. The most striking result of these studies is 

 that the condensation in the Milky Way seems to commence with the 

 brightest stars. A little consideration will show that we cannot, with 

 any probability, look for such a condensation in the case of stars 

 near to us. Whatever form we assign to the stellar universe, we shall 

 expect the stars immediately around us to be equally distributed in 

 every direction. Not until we approach the boundary of the universe in 

 one direction, or some great masses like those of the galaxy in another 

 direction, should we expect marked condensation round the galactic 

 belt. Of course we might imagine that even the nearest stars are most 

 numerous in the direction round the galactic circle. But this would 

 imply an extremely unlikely arrangement, our system being as it were 

 at the point of a cone. It is clear that if such were the case for one 

 point, it could not be true if our Sun were placed anywhere except at 

 this particular point. Such an arrangement of the stars round us 

 is outside of all reasonable probability. Independent evidence of the 

 equal distribution of the stars will hereafter be found in the proper 

 motions. If then, the nearer stars are equally distributed round us, 

 and only distant ones can show a condensation toward the Milky Way, 

 it follows that among the distant stars are some of the brightest in the 

 heavens, a fact which we have already shown to follow from other 

 considerations. 



Very remarkable is the fact", pointed out first by Sir J. Herschel and 

 heavens very nearly in a great circle, but not exactly in the Milky Way. 

 heavens very nearly in a great circle, but not exactly in the Milky Way. 

 In the northern heavens the brightest stars in Orion, Taurus, Cassiopeia, 

 being near the Southern Cross and the other in Cassiopeia. This belt 

 includes the brightest stars in a number of constellations, from Canis 

 Major through the southern region of the heavens and back to Scorpius. 

 In the northern heavens the brightest stars in Orion, Taurus, Cassiopeia, 

 Cygnus and Lyra belong to this belt. It would not be safe, however, to 

 assume that the existence of this belt results from anything but the 

 chance distribution of the few bright stars which form it. In order to 

 reach a definite conclusion bearing on the structure of the heavens, 



