a The Saturnian System. {January, 
reference to familiar terrestrial relations. For instance, if 
the satellites of Saturn are referred to, the remark is made 
that the external skies of Saturn must be well illuminated, 
and very beautiful with all these moons, when our own 
single moon forms so beautiful a feature of our nights. 
When the rapid rotation of Saturn is mentioned, we are 
told immediately that therefore the day in Saturn lasts only 
so many of our hours. So withthe Saturnian year, because 
the mean density of Saturn is but about 13-1ooths 
of the earth’s; we are told that, therefore, his globe is 
construéted of material as light as ‘mahogany ; and so on, 
through a variety of such comparisons. 
It appears to me that the history of investigations into 
the physical condition of the planets is chara¢terised by a 
very singular unreadiness to view the whole subject from 
the new standpoint, available when telescopic observations 
began to be made. The new knowledge gained by means 
of the telescope was welded to the old ideas respecting 
the planets. New cloth was added to old garments. The 
natural course, one would have supposed, would have been 
to consider the planets altogether in the light of information 
obtained by the telescope, simply because that was the first 
really reliable information obtained by astronomers. Every- 
thing until then had been guess work; yet the results of 
such guess work still appears in our books on astronomy. 
It is not Saturn or Jupiter, as revealed by the telescope, 
with which our writers on astronomy deal; but they tell us, 
in effect, that the Saturn and Jupiter of the old astronomers 
have been found to have such and such dimensions, 
rotation-rates, aspect, and so on. 
Accordingly, the attempt to reason respe¢ting these planets 
in perfect independence of the ideas entertained ages ago by 
astronomers, is regarded as a species of innovation. That 
is held to be rash and fanciful speculation which in point of 
fact is the only scientific way of treating the subject. It is 
held to be a sort of heresy to speak of Saturn or Jupiter 
in terms not stri€tly compatible with the words of Sir 
W. Herschel, for example, although his ideas respe¢ting 
these planets were based entirely on the ideas formerly 
entertained about them, and conveyed to Sir W. Herschel 
through the instruCtive but not very suggestive teachings of 
Ferguson. I have not, indeed, myself had to complain on 
this point. I have, in faét, been surprised at the exceedingly 
liberal manner in which my own theoretical opinions have 
been received—I may even say welcomed—by many who, | 
nevertheless, still retain a prejudice for the older way of 
