310 The Construction of the Heavens. [July, 
not discuss in any way the relations presented by the stars. 
Huyghens, however, in his ‘‘ Cosmotheoros,”’ made many 
judicious reflections respecting the stellar system, and 
advanced opinions which were carefully based on observed 
facts. We owe to him the definite enunciation of the 
theory that the stars are suns like our own, probably, like it, 
the centre of planetary schemes. Huyghens, like his pre- 
decessors, failed to discuss attentively the configuration 
of the star groups, whether those seen by the naked eye or 
those revealed in the telescope, with the purpose of thence 
ascertaining the laws according to which the stellar universe 
is constituted. Newton, Halley, Flamsteed, and their con- 
temporaries, paid in like manner very little attention, or 
none at all, to that stupendous problem, the solution of 
which Sir W. Herschel afterwards set before him as ‘“ the 
ultimate object of his observations.” And passing at a step 
over the interval separating Newton’s day from our own 
times, it may be said that the Herschels and the elder 
Struve have been the only astronomers who have attempted 
to form broad and connected views respecting the structure 
of the universe, while only half-a-dozen names need be 
added, if we would include those who have given attention 
to the subordinate problems associated with the great one of 
determining the laws of the sidereal system. 
But even more remarkable than the carelessness with 
which nearly all the great astronomers of the last three 
centuries have viewed this noble problem, is the faé¢t that 
attention was first fairly called to the problem, and worthy 
attempts were first made towards its solution, by men who 
were not astronomers* in the true sense of the term, and 
whose names, with a single exception, remain in un- 
deserved obscurity. How seldom do we hear the names of 
* Lest this remark should be misunderstood, I may as well explain in what 
sense I use the word astronomer. I was somewhat roundly taken to task 
when in the first edition of my ‘‘ Other Worlds” I spoke of Whewell in one 
place, and of Humboldt in another, as not being astronomers. There cannot be 
any question that Whewell had a clearer insight into many astronomical 
subjects than many who must be described as astronomers; and a like remark 
applies to Humboldt, Brewster, and others, as well as to these of whom 
I speak above. Yet it is impossible for any astronomer to read many consecu- 
tive pages of matter written on astronomical subjects by Whewell, Humboldt, 
Brewster, Kant, and others, without feeling that they were emphatically not 
astronomers. What then, it may be asked, is my definition of an astronomer ? 
It is one which immediately removes anything that might seem invidious in the 
distinction I draw between the above-mentioned eminent men, and others—not 
more eminent, some far less eminent—whom I should emphatically call astro- 
nomers. An astronomer is one who devotes the main portion of his scientific 
life and labour to the study of astronomy, either generally or in some special 
department. This definition excludes, and, as I take it, properly excludes, 
