March 30, 191 1] 



NATURE 



149 



one centre the committee system is brought to bear 

 on the most trivial details of domestic management ; 

 in another case a central authority practically decides 

 even such matters as forfeiture of scholarships in cases 

 of discipline. It may be that these divergences are 

 the result of varying local conditions, but a study of 

 them might well be extended to our universities. 



Since the preceding notice was written, we have 

 received a criticism of Mr. Cooke's report by President 

 R. C. Maclaurin, of the Massachussets Institute of 

 Technology, published in Science, xxxiii., 838, pp. 

 101-103 (January 20). Attention is particularly directed 

 to the fact that most of the points raised in the report 

 are not new. " It is full of commonplaces, and there 

 is scarcely a question raised that has not been dis- 

 cussed ad nauseam by college professors and other 

 officers. It is not lacking in confidence. One marvels 

 at the temerity even of an ' eflficiency engineer ' who 

 can lay down the law so definitely as to how to teach 

 physics, how to conduct a recitation, how to carry on 

 research, when most of us who have devoted our whole 

 lives to such problems are far less confident." Presi- 

 dent Maclaurin specially condemns the " student- 

 hour " standard of efficiency and the proposal for in- 

 spection of research, the futility of which has been 

 pointed out above, and he instances his point by the 

 following imaginary dialogue between Newton and 

 the " superintendent of buildings and grounds, or 

 other competent authority." 



''Superintendent: Your theory of gravitation is 

 hanging fire unduly. The director insists on a finished 

 report, filed in his ofilice, by g a.m. Monday next, type- 

 written, and the main points underlined. Also a care- 

 ful estimate of the cost of the research per student- 

 hour. 



" Newton : But there is one difficulty that has been 

 puzzling me for fourteen years, and I am not quite . . . 



''Superintendent (with snap and vigour): Guess 

 you had better overcome that difficulty by Monday 

 morning or ouit." 



G. H. Bryan. 



THE MOTIONS OF THE TLANETS JUPITER 

 AND SATURN. 



THE January number of the South African Journal 

 of Science contains an excellent paper by Mr. 

 R. T. A. Innes on Le Verrier's theory of the motion 

 of the planets Jupiter and Saturn. The title scarcely 

 covers all that is in the paper, for the author con- 

 cludes with numerical calculations, based upon for- 

 mulae developed by himself in the Monthly Notices 

 for 1909, which must constitute a considerable step 

 towards a revision of Le Verrier's theory. 



Mr. Innes's chief criticism on Le Verrier is that 

 he has taken 9'73674o8 instead of 9*73655 14 for the 

 log ratio of the mean distances of Jupiter and Saturn, 

 an error approximately of one part in two thousand. 



The error is, however, considerably magnified when 

 its effects upon the series representing the reciprocal 

 of the distance between Jupiter and .Saturn are con- 

 sidered, and the author's final conclusion is that the 

 fourth significant figure always, and the third often, 

 is incorrect in Le Verrier's perturbations. The error 

 arose because Le Verrier used the mean distances 

 corresponding in elliptic theory with the mean motions 

 and neglected the systematic effects of the perturba- 

 tions. Jupiter, for instance, on a distant planet like 

 Neptune, may be approximately considered as 

 coalescing with the sun, making that body heavier 

 bv one-thousandth part, and consequently the mean 

 distance of Neptune greater by one part in three 

 thousand. 



NO. 2 161, VOL. 86] 



The mean distance of Saturn needs correction by 

 a greater fraction, nearly one part in two thousand; 

 for when Jupiter is between Saturn and the sun, its 

 attraction amounts to about four parts in a thousand 

 of that of the sun, and the average is thus raised. 



Le Verrier's omission is unimportant in all other 

 cases. For the four inner planets the perturbations 

 are so small that the third significant figure is in- 

 sensible, and for Neptune and Uranus the increment 

 due to Jupiter is practically the same and the ratio 

 inappreciably altered. 



We quote, for ready reference, a most valuable 

 table :— 



Planet 



Mercury 



Venus 



Earth 



Mars 



Jupiter 



Saturn 



Uranus 



Neptune 



Log mean distance 



Elliptic theory 

 9-5878 2168 

 9-8593 3781 



o"oooo coo I 

 0-1828 9703 

 07162 3747 

 0-9794 9655 

 1-2829 0024 

 1-4779 4661 



Actual 

 9-5878 2160 



9 8593 3745 

 00000 0012 

 0-1828 9616 

 0-7162 3339 

 0-9796 7915 

 1-2830 9713 

 1-4781 4316 



Some obiter dicta in the paper are of great interest. 

 Here is one : — 



" So far as merely obtaining an ephemeris goes, 

 it is probable that the method of special perturbations 

 would have given one for 300 years or so with less 

 labour than was involved in either the theories of Hill 

 or Le Verrier." 



This sets one thinking why we want the theories. 

 Of course, we want the general results of theory, the 

 first and foremost being that the mean distances are 

 subject to no secular changes. And we want the out- 

 line of the theory of long-period inequalities with 

 rough estimates of the numerical coefficients. But 

 an ephemeris of Neptune could be obtained by special 

 perturbations at 512-day intervals (using a power of 

 2); fifty intervals of 512 days each would cover the 

 period from its discovery to the present day — a month's 

 work. 



It is beginning to be recognised that the " theorv, 

 good for ages, in which t alone has to be substituted," 

 is incomplete. Le Verrier gave some results for the 

 earth 100,000 years ago, based on his theory. If 

 similar theories existed for the minor planets, we 

 doubt, if we should see Eros falling within the orbit 

 of Mars, the Trojan group being captured by Jupiter, 

 and the zone corresponding to a mean motion double 

 that of Jupiter being cleared of small planets. Pos- 

 sibly these phenomena are due to the secular effects 

 of small causes not at present taken into account. 

 We want, therefore, in the cheapest possible way, to 

 multiply accurate ephemerides for comparison with 

 observation. 



THE ANTON DOHRN MEMORIAL FUND. 



THE zoological station at Naples occupies a unique 

 position among the biological institutions of the 

 world. It is not only the oldest, the largest, and the 

 best equipped of the biological stations, but it has. 

 maintained throughout its existence its thoroughly 

 international character. The founder of this impor- 

 tant institution. Dr. Anton Dohrn, died on September 

 26, 1909, and at the eighth International Zoological 

 Congress, held at Graz during August, 1910, it was 

 decided to raise a fund for an international memorial, 

 to commemorate his great achievement. 



In case some doubt may be entertained as to the 

 maintenance of the international character of the- 

 institution which is now under the management of 

 Prof. Reinhard Dohrn, one of the sons of the distin- 

 guished founder, it may be remarked that Prof, vork 



