262 SPECIAL 11ESULTS IN THE UltANOLOGICAL 



that of the determination of positions in Eight Ascension 

 and Declination, whether of single fixed stars, or of double 

 stars, star-clusters, and nebulae. Measurable relations of a 

 more difficult class, but yet susceptible of a greater or less 

 degree of accuracy, are presented by the proper motion of 

 stars ; the elements by means of which their parallax may 

 be sought; telescopic star-gaugings, throwing light on 

 their distribution in space; and the periods of variable 

 stars and slow revolutions of double-stars. Subjects which 

 by their nature escape from the domain of measurement, 

 properly so called, such as the relative position and the 

 forms of sidereal strata or annuli ; the arrangement of the 

 structure of the universe ; the effects of rapidly transforming 

 natural agencies ( 461 ) in the blazing forth and speedily suc- 

 ceeding extinction of what have been called new stars, all 

 affect the inind the more vividly and profoundly from the 

 wide scope which they furnish to the fascinating exercise of 

 the imaginative faculties. 



We purposely abstain in the following pages from all 

 considerations respecting the connection of our solar system 

 with the systems of the other fixed stars ; we do not propose 

 to return to questions respecting the subordination and mutual 

 dependence of different systems, questions which appear to 

 grow out of what are felt to be intellectual wants ; as for 

 example, whether our sun be not itself in a state of planetary 

 dependence on a higher system, perhaps not even as a 

 primary planet, but only as the satellite of a planet, like the 

 moons of Jupiter in our own system. We limit ourselves to the 

 home circle of the solar domain itself; and in doing so we 

 enjoy the advantage that, with the exception of what relates 



