Nov. 27, 1879] 



NATURE 



8? 



four or more, the physico-chemical and geological ques- 

 tions ; that the latter should have a separate class-list 

 and days of examination, with four written papers of 

 three rows each, and a practical examination ; and that 

 the biological examination should have four papers and 

 be in other respects similarly conducted, letting no special 

 marks of distinction be given. Few first-rate candidates 

 would desire to take both these examinations, and if they 

 desire further distinction in particular subjects, original 

 work in research or authorship, is surely the best test ; 

 and the University might subsequently give to competent 

 men degrees in science which now it unfairly cannot 

 give; the degree of Doctor of Science should be given 

 to men qualified to be University Readers or Professors 

 in Science. 



Mr. Hillhouse, of Trinity, the Assistant Curator of the 

 Cambridge Herbarium, and one of the editors of the 

 Cambridge Review, in an article last week, admits that 

 which many promoters of learning might think a sign of 

 ■unrest and indecision, rather than of real growth, namely, 

 that the regulations issued by the Board of Natural 

 Sciences Studies [must be very mutable, and continually 

 need revision. As to the argument for human anatomy as 

 such receiving a prominent place in a tripos, Mr. Hill- 

 house says it rests on the fallacy that men are likely to 

 study a subject with more interest if it is made a subject 

 of a tripos, than if it is included in the M.B. But, his 

 experience is, the man who will not work for his M.B. 

 will surely not work for his tripos ; if anything, he will 

 work better for M.B. than tripos. 



The University of London, having for a long time 

 required all candidates for the degree of B.Sc. to pass in 

 elementary mathematics, physics, geology, palaeontology, 

 and the other biological sciences, as well as logic, has 

 now reverted to the wiser plan of examining at its 1st 

 B.Sc. in elementary mathematics, physics, inorganic 

 chemistry, and elementary biology, and at the degree 

 examination (for B.Sc), giving the degree for passing in 

 three out of nine divisions of sciences, so that a biological 

 student may, if he chooses, enter for a very clearly-detined 

 examination in botany, zoology, and physiology. The Cam- 

 bridge man will then soon prefer the B.Sc. Lond., with the 

 subsequent possibility of a doctorship in science, given for 

 thorough attainment in the special subject of his life-study 

 and teaching, unless biology receives fair play at Cam- 

 bridge. Why is it that Martin, Hartog, Marshall, and Vines 

 havetaken their D.Sc. (Lond.), to mention biologists only? 

 It is surely not that they are devoted to examinations, but 

 that Cambridge was not yet able to give them the distinc- 

 tion in their chosen subjects which they were entitled to 

 demand. Biology, worthy of the name, is still to a very 

 considerable extent proscribed or suspected in Cam- 

 bridge. In a future age how strange a survival of 

 prejudice this will seem. G. T. Bettaxv 



THE PLANETS OF THE SEASON 

 Saturn 

 "IXTE recently called the attention of our astronomical 

 *» readers to that noble planet, the captain of our 

 celestial guard, those three that keep the mid-watch of 

 the night in an imposing order that may not return for 

 ages ; at distances nearly equal, and in a line not widely 

 deviating from a great circle of the sphere. Saturn, the 

 next in position, may now be the subject of a cursory 

 notice. 



The aspect of this most interesting of the planets is at 

 the present time singularly elegant and attractive. The 

 relief, however, is delicate, and the details not conspicu- 

 ous ; but though the presentation may be less adapted 

 for a close scrutiny than that of either the full opening or 

 the evanescent phasis of the ring, its examination will 

 not fail to reward the careful observer. 



Schroter had a true insight into the pervading charac- 

 ter of the universe when he described it as uniform in phn, 

 with an endless variety in detail. Such is evidently the 

 case with the planetary system. We find everywhere 

 arrangements in part closely parallel or even identical 

 with those most familiar to us, in part so rapidly diver- 

 gent that the connecting analogies are strained, and thin 

 away, as it were, till the bond of union can be traced no 

 longer. Saturn is a complete instance of this. The 

 dependence on the great central ruler, the spherical 

 form, the polar flattening, the rotation on an inclined 

 axis, the accompaniment of an atmosphere — all corre- 

 spond with our own ; while the differences, not only in 

 magnitude, but in density and the force of gravity, are 

 so great that we cannot even guess at the component 

 materials. We endeavoured lately to point out how 

 limited is our knowledge of Jupiter, though in various 

 ways favourably circumstanced for observation ; but on 

 Saturn, with the exception of his change of seasons, we 

 should find ourselves still greater strangers ; and the 

 terrestrial analogies that aided us so little there would here 

 be of still less service. Every difficulty is magnified by the 

 vast increase of distance and defalcation of light ; we can 

 only record what we see, and much of that is neither 

 familiar nor intelligible. 



It is easy, however, to perceive a strong general resem- 

 blance between these two great globes, not only in gigantic 

 dimensions, want of density, and velocity of rotation, but 

 in various atmospheric characteristics, such as parallelism 

 of direction (sometimes, according to Herschel I., not 

 quite equatorial on Saturn), contrasted colouring, and the 

 occasional formation of bright and obscure patches. And 

 yet in one main feature there is a very marked dissimi- 

 larity — the position of their axes. In this one point 

 Saturn, after a decided interruption in the series, reverts 

 to the type of the earth and Mars. And it is scarcely 

 conceivable that the presence or absence of a change of 

 seasons should not be strongly felt in its effects. One 

 result, however, which might on a superficial view have 

 been expected, is absent from Saturn. There is no 

 luminous deposit around the poles, which, on the con- 

 trary, are often more dusky than the equatorial regions, 

 and this alone would infer a different atmospheric consti- 

 tution from our own, even if we left out of sight the 

 consideration that such might well be expected when the 

 subjacent materials are as light as cork, and the whole 

 globe would float high out of water. But for this curious 

 deviation from regular sequence — a kind of deviation 

 so remarkable and so significant in the planetary system 

 —we should have remarked as complete an analogy 

 between Jupiter and Saturn as that which is believed to 

 obtain between the Earth and Mars. 



The changes, however, in the atmosphere of Saturn 

 are not usually so conspicuous as those on Jupiter ; nor is 

 this to be wondered at, when we consider its inferior 

 brilliancy at a distance measured by hundreds of millions 

 of miles. The equatorial zone is usually represented as 

 of prominent and unvaried brightness, and the dusky- 

 belts differ much in depth and arrangement at different 

 times. Luminous and dark patches, though not common, 

 are far from being unknown. The white equatorial spot, 

 resolving itself ultimately into a streak, which was ob- 

 served by Hall in 1876, though not, as has been asserted, 

 an unprecedented, was a very remarkable instance of the 

 former class, as one perceived by Herschel I., ninety-six 

 years before, had been of the latter. This dusky spot 

 was situated near the limb, where on Jupiter it would 

 presumably have been invisible ; yet much could not be 

 inferred from this solitary observation, nor from that of 

 Chacornac on the transit of the largest satellite, which 

 showed a limb more luminous than the centre of the disk. 

 Everything of this kind should be noted, but nothing 

 pressed into the service of a foregone theory. 



The flattening of the sphere at the equator, as well as 



