Feb. 19, 1 8 74 J 



NA TURE 



3" 



promising opposition of 1877 ; when, if the seasons on 

 both planets are as favourable as their mutual proximity, 

 we m ly reasonably expect some advance to be in store 

 for us. The great object will natuiMlly be the identifica- 

 tion of the dark spots, as well as a more careful delinea- 

 tion of their boundaries : attention will doubtless be paid 

 towards obtaining a definitive value for the rotation ; but 

 in this direction progress is not very material, as we have 

 already a sufficient approximation. Those who would 

 see an extraordinary instance of the most painstaking 

 and protracted efforts to get rid of a trifling uncertainty 

 may apply themselves to the 23 pages of Kaiser, in which 

 all kinds of varied combinations are tiled to reconcile some 

 conflicting decimals of a s.;cond, for to these the question 

 is reduced at last. Cassini, as far back as 1666, had fi.xed 

 the rotation at 2411. 40m. with surprising correctness for 

 his day. Herschel I. brought it to 24h. 39m. 2I'673. 

 but, as Beer and Madler perceived, the omission of one 

 rotation, and of the effects of phasis and aberration, 

 vitiated the result. They in turn gave 24h. 37m. 237s. 

 Kaiser, from many elaborate comparisons, deduced a 

 mean of 22'63s., but Proctor having found a value of 

 22735s. the former, who thought the English astronomer's 

 coincidences illusory, went into the whole subject afresh 

 with marvellous minuteness, and got out a final mean of 

 22'53is., discovering by the way some unexpected in- 

 accuracies, convincing himself that the correctness of 

 the best drawings has been greatly over-rated, and finally, 

 in much mortified perplexity, leaving it to every one to 

 choose his own combniation. No computation, he says, 

 can make us sure to the hundredth of a second ; and unless 

 observations become very much more precise, it will be 

 several centuries belorc such a result will be obtained : 

 how much the wiser mankind would be for it, is another 

 question, which we need not discuss here. But there is, 

 perhaps, no great difficulty in divining the cause of the 

 Professor's troubles. Epochs of rotation could only be 

 safely taken from drawings made with that special 

 object, and few such probably exist ; the designer 

 usually either contenting himself with a general likeness, 

 or being occupied about details, the study of which would 

 of itself render him less attentive to mere position. In 

 future, these objects might be better separated ; and 

 while the artist busies himself with the iiiiitutia: of the 

 picture, the rotation- seeker should employ himself e.K- 

 clusively in estimating the co-ordinates of some con- 

 spicuous points — a process which admits of a mean 

 taken between many proportional valuations. 



Several other desirable matters' of inquiry will readily 

 offer themselves. Measures of ellipticity have as yet 

 yielded only contradictory results. The inclination of 

 the axis, last deduced by Oudemans in 1852, may 

 be susceptible of correction ; and the excentric 

 position of one or both of the snow-spots, and the un- 

 symmetrical position of the isothermal poles, would be 

 matters of interesting investigation. The amount of the 

 latter deviation, first measured by the elder Herschel, 

 has been given so very differently by different observers, 

 even at the same opposition, that it evidently is open to 

 fresh determination. Tlic well-known colours will of 

 course catch the eye ; and attention may be paid to the 

 question whether the green, or as others think blue, tint 

 of the dark parts (which Kaiser saw as grey only) is 

 really, as Herschel Il.implifS, the mere result of contract. 

 The effect may be possibly thus heightened; but no one 

 who saw one of the great seas as the writer did with a 

 gin. silvered speculum on April 4, 1871, could doubt the 

 independent existence of a beautiful clear blue grey tint, 

 the more certain as a shading on another part of the 

 disc was of a brownish hue : nor does it seem to have 

 been noticed that no effect of contrast has been traced 

 in the polar snows. The luminous and occasionally 

 coloured patches and segments on the limb should receive 

 attention, and the position of " Dawes' ice-island" be scru- 



tinised ; such a brilliant speck I witnessed at the above 

 epoch, but I believe in another situation. Black points 

 should be looked for, as such have been detected by 

 I\Iitchell and Dawes ; and it should be noted at the time 

 of any conspicuous feebleness of the markings, whether 

 the sharpness of the limb indicates the cause to be further 

 distant than our own atmosphere : and in general the 

 " daily — nay, hourly — changes in the detail and in the 

 tones of the different parts of the planet, b Hh light and 

 dark," described by Lockyer, should be carefully watched 

 and recorded ; 



" In tenui labor ; " 

 nevertheless, none of these little matters will be con- 

 sidered insignificant by those who love to behold in such 

 things the lootsteps of Creative and Upholding Power. 



T. W. Webb 



NOTES 



We have received some interesting notes of the work done by 

 the eminent Russian explorer. Dr. von Miclucho-Maclay, which 

 we hope to publish next week. Contrary to the advice of eveiy- 

 one, this intrepid traveller and true devotee of Science is deter- 

 mined upon again visiting the east coast of Papua. When his 

 researches here are complete he intends to visit some of the islands 

 of Polynesia and certain parts of the coast of Austr.alia, This, he 

 calculates, will take up five or six years. The Governor of the 

 Dutch East Indies, like a true man of Science, had given Dr. 

 Maclay, for the last six months, roomy and comfortable quarters 

 in his palace at Buitonrovg. It would be well, if all in hi^h 

 position would imitate this kind of " patronage." 



The Meteorological Committee of the Board of Trade have 

 resolved to commence the issue of lithographed copies of the 

 twenty-four hourly tabulated readings, taken at their seven ob- 

 servatories, for every element which is observed continuously, 

 commencing with January I, 1S74. The sheets wdl be issued 

 quarterly, and the issue will be a limited one. The subscription 

 for a copy is l/. per annum, to cover a portion of the expense of 

 production. The sheets will not be distributed with the publica- 

 tions of the ofHce. 



M. L. QUETELET, the founder and director of the BiusseU 

 Observatory, died in Brussels on Monday night, aged 77. lie 

 leaves a son, M. Ernest Quetelet, wiio inherits the scientific 

 enthusiasm of his father. 



The letter which has been received from Consul Prideaux, 

 and the extract from Cameron's letter published in the Acndeiny, 

 adds but little to the details we gave some time ago concerning 

 Livingstone's reported death. Lake Bemba is identified by 

 Consul Prideaux as Lake Bangweolo, and a letter from the Arab 

 Governor of Unyanyembe fixes the spot where the great 

 traveller died at Lobisa. A letter to Dr. Petermann from 

 the German African traveller and Austrian Consul at Zan- 

 zibar, Mr. Richard Brenner, merely repeats the statements 

 already known. Dr. Kirk, under date Feb. 12, writes to the 

 Acailciiiy as follows: — "Th's morning I have heard indirectly 

 from Zanzibar, and find people there who could judge, still 

 question the truth of the story ot Livingstone's death. Like 

 us, they see nothing but native report to base it on." Let us 

 hope that this is the real state of the case. As Zanzibar and 

 Ujiji are at present at peace it is expected that there will be 

 no difficulty hi getting the Doctor's valuable journals. It 

 is gratifying to see from Mr. Markham's letter in yesterday's 

 Tiiiiis that through Sir Samuel Baker's determined energy, 

 the route to Zanzibar has been virtually opened up from the north. 



The letter above referred to from Consul Brenner, states that 

 a German botanist, M. Hildebrand, has been preparing, (or a 

 year past, to undertake a journey mto the interior of the GaUa 

 country and Somali Land. 



