1874.) — The Saturnian System. 3 
treating the subject. But I observe that other writers have 
been less fortunate; and when they have indicated the 
significance of the features which distinguish giant planets 
from the terrestrial planets, and touch on some of the 
conclusions flowing from such considerations, their views 
are scouted as wild and fanciful—too startling, in fact, to 
obtain acceptance among men of science. 
In passing, I would touch on the objection to startling 
views, merely because they are startling, as utterly unreason- 
able in the presence of all that has been discovered, not 
merely in astronomy, but in science generally. The accepted 
truths of science are nearly always startlingly unlike what 
has been imagined before the evidence became strong 
enough, or was well studied enough, to indicate the real 
facts. Take, for instance, what has been learned recently 
about the sun. Suppose that twenty years ago the now 
known truths about the constitution of the sun, about 
coloured prominences, and about the corona had _ been 
simply enumerated, either as the result of theoretical 
considerations or of observations the nature of which was 
not made known: then it is certain that the surprising 
character of these new views would have _ rendered 
them unwelcome to astronomers. Less startling theories 
would have been received with favour, and quoted as 
altogether preferable to notions so bizarre and fanciful; yet 
the sober theories of twenty years ago were wide of the 
truth. They were in reality fanciful, and though not far 
fetched, yet ill fetched ; drawn, in fact, from utterly incorrect 
analogies. 
It may be assumed, indeed, ordinarily, that the relations 
as yet unknown are such as we should regard as surprising. 
It is not merely an unsafe, but an almost certainly mis- 
leading assumption that the best explanation of facts is the 
one which is most obvious and natural. What can be 
more natural, for instance, than the theory that the solar 
corona is due to the passage of the sun’s rays through our 
own atmosphere ?—what more utterly misleading? How 
natural was Faye’s theory that the solar sierra is a 
phenomenon produced by the lunar atmosphere; and yet 
the theory was altogether and demonstrably unsound. ‘To 
go farther back in the history of astronomy, the Ptolemaic 
theory was unquestionably intended to explain in the most 
natural way the celestial motions observed from our earth, 
obviously fixed, obviously far larger than any of the heavenly 
orbs. Even more natural and seemingly obvious is the 
theory that the earth is a great plain. ‘The true theory in 
