Mr Hinks, Suggestions for a theory of the Milky Way, etc. 201 



Suggestions for a theory of the Milky Way arid the Clouds 

 of Magellan. By Arthur R. Hinks, M.A., Trinity College. 



[Read 13 November 1905.] 



In the northern hemisphere the stars in general, the coarse 

 clusters, the gaseous nebulae, and especially the stars with bright 

 line spectra of Pickering's type V, are concentrated upon the 

 plane of the Milky Way, while the spiral nebulae seem to avoid it. 

 In the southern hemisphere the stars and coarse clusters, the 

 gaseous nebulae, and the type V stars are concentrated in the 

 Milky Way, and the greater Cloud of Magellan ; the nebulae 

 which are presumably spiral — (photographic evidence of the 

 structure has not yet been obtained) — tend to avoid the Milky 

 Way, as in the North, but crowd into the greater cloud to meet 

 those Milky Way constituents with which they are associated 

 nowhere else. 



It is generally assumed that this fact is of the highest signifi- 

 cance. Its significance depends, however, upon the view that may 

 be taken of Herbert Spencer's proposition, enunciated in the year 

 1858, that the stars and nebulae are so definitely separated that 

 they must necessarily be complementary parts of one general 

 scheme of creation. The basis of this proposition is evidently the 

 assumption' that the stars are symmetrically condensed upon the 

 plane of the Milky Way, the spiral nebulae symmetrically con- 

 densed about its poles. If that were so, it would be necessary to 

 look for some separative influence which had driven those stars 

 and nebulae apart, except in one particular region of the sky ; and 

 it would be natural to look in that exceptional region, the greater 

 Magellanic cloud, for some hint as to the nature of the influence 

 which there only had failed to operate. 



It appears, however, to the author, that the evidence is very 

 far from being so strong as to compel the adoption of this line of 

 reasoning. 



The great masses of the fainter stars are disposed in the 

 irregular but sharply bounded star clouds which correspond very 

 closely to the visual form of the Milky Way, and evidently produce 

 that form. 



The stars of the eleventh magnitude and brighter have little 

 connection with the apparent structure of the Milky Way. On 

 the whole they increase in numbers towards its plane, but their 

 distribution in galactic longitude is far from uniform. A study of 

 distribution charts such as those of Stratonoff (Publ. de I'Observa- 

 toire de Tachkent, 2 and 3) suggests rather that these stars are also 

 arranged in clouds, of greater apparent extent than the Milky 

 Way star clouds, and probably nearer the Sun, but more or less in 

 the same plane with them. 



