150 COSMOS. 



ually look through as into free space. " It leads us," says 

 Sir John Herschel, " irresistibly to the conclusion that in 

 these regions we see fairly through the starry stratum."* 

 In other regions we see, as it were, through openings and 

 fissures, remote world-islands, or outbranching portions of the 

 annular system ; in other parts, again, the Milky Way has 

 hitherto been fathomless, even with the forty-feet telescope. f 

 Investigations on the different intensity of light in the Milky 

 Way, as well as on the magnitudes of the stars, which regu- 

 larly increase in number from the galactic poles to the circle 

 itself (an increase especially observable for 30° on either side 

 of the Milky Way in stars below the eleventh magnitude, $ 

 and therefore in |^ tns °f a ^ tne stars), have led the most 

 recent investigator of the southern hemisphere to remarkable 

 views and probable results in reference to the form of the 

 galactic annular system, and what has been boldly called 

 the sun's place in the world-island to which this annular 

 system belongs. The place assigned to the sun is eccentric, 

 and probably near a point where the stratum bifurcates or 

 spreads itself out into two sheets, § in one of those desert re- 

 gions lying nearer to the Southern Cross than to the oppo- 

 site node of the Milky Way.|| "The depth at which our 

 system is plunged in the sidereal stratum constituting the 

 galaxy, reckoning from the southern surface or limit of that 



* Outlines, p. 536, 537, where we find the following words on the 

 same subject : " In such cases it is equally impossible not to perceive 

 that we are looking through a sheet of stars nearly of a size, and of 

 no great thickness compared with the distance which separates them 

 from us." 



t Struve, Etudes StelL, p. 63. Sometimes the largest instruments 

 reach a portion of the heavens, in which the existence of a starry stra- 

 tum, shining at a remote distance, is only announced by " a uniform 

 dotting or stippling of the field of view." See, in Observations at the 

 Cape, p. 390, the section M On some indications of very remote tele- 

 scopic branches of the Milky Way, or of an independent sidereal sys- 

 tem or systems bearing a resemblance to such branches." 



t Observations at the Cape, § 314. 



§ Sir William Herschel, in the Philos. Transact, for 1785, p. 21 ; Sir 

 John Herschel, Observations at the Cape, § 293. Compare also Struve, 

 Descr. de V Observatoire de Poulkova, 1845, p. 267-271. 



|| " I think," says Sir John Herschel, " it is impossible to view this 

 splendid zone from a Centauii to the Cross without an impression 

 amounting almost to conviction that the Milky Way is not a mere stra- 

 tum, but annular ; or, at least, that our system is placed within one of 

 the poorer or almost vacant parts of its general mass, and that eccen- 

 trically, so as to be much nearer to the region about the Cross than to 

 that diametrically opposite to it." (Mary Somerville, On the Conner 

 *ion of the Physical Sciences, 1846, p. 419.) 



