126 SPECIAL RESULTS IN THE URANOLOGICAL PORTION 



powerful telescopes (and we must remember that, according 

 to the estimations of Sir William Herschel, a 20-feet in- 

 strument penetrates space to 900, and a 40 -feet instrument 

 to 2800 distances of Sirius), the Milky Way appears in 

 different parts as varied in its sidereal contents, as it seems 

 irregular and indeterminate in its outlines arid boundary 

 when viewed by the naked eye. If in some parts of the 

 Milky Way large spaces exhibit great uniformity, both in 

 respect to light and to the apparent magnitude of the stars 

 of which it consists, in other parts the brightest patches of 

 closely-crowded luminous points are interrupted in a 

 granular, and even in a reticular manner, by darker inter- 

 vals ( 253 ) which are poor in stars : indeed, in some of these 

 intervals, quite in the interior of the galaxy, not even the 

 smallest star (18th or 20th magnitude) can be discovered. 

 One can hardly refrain from thinking, that in such places 

 we really see through the whole sidereal stratum of the 

 Milky Way. When gauging with a field of view of the 

 telescope of 15' diameter, the change is almost immediate 

 from fields containing 40 or 50 stars on an average, to others 

 having between 400 and 500 stars. Often, stars of the higher 

 orders of magnitude occur in the midst of the finest " star 

 dust," while all the intermediate magnitudes are wanting. 

 Perhaps those stars which we call of the lower orders of 

 magnitude do not always appear to us such solely on ac- 

 count of their enormous distance : it is also possible that they 

 may really have less volume and less development of light. 



In order to represent to ourselves the greatest contrast, 

 in respect to abundance or paucity of stars, we must take 

 regions widely removed from each other. The maximum of 

 accumulation and the greatest brilliancy are to be found 



