498 



NATURE 



[March 26, 1896 



have less rain, and less contrasts also. On the north-east of the 

 peninsula of Celebes the rains are comparatively light, and there 

 is a well-marked dry season. In Java, the rainfall is lightest in 

 the east, and the dry season is longer and more sharply defined, 

 so that vegetation has a time of arrest corresponding to our 

 winter.— Psychrometer studies, by Prof. H. A. Hazen. This is 

 a continuation of a discussion between Prof. Hazen and Dr. 

 Ekholm, of Stockholm, on the behaviour of the psychrometer 

 •with respect to water vapour and ice vapour. 



Bulletin of the American Mathematical Society, vol. ii. No. 5, 

 February. — " Remarks on the progress of celestial mechanics 

 since the middle of the century " is the presidential address de- 

 livered before the Society on December 27, 1895, ^Y Dr. G. W. 

 Hill. The address opens with the statement that a thoroughly 

 satisfactory history of the subject has yet to be written, and then 

 the author rapidly analyses some of the books that touch upon 

 it, as Gautier's " Essai historique sur le probleme du trois 

 corps" (1817), Laplace's historical chapters in the last volume 

 of the " Mecanique Celeste," Todhunter's " History of the 

 Theories of Attraction and the Figure of the Earth," and Tis- 

 serand's " Traite de Mecanique Celeste." The scarcity of 

 memoirs and books on the same subject accessible to American 

 students, unless they work abroad, is dwelt upon, and then Dr. 

 Hill opens with a consideration of Delaunay's method {cf. his 

 *' Theorie du Mouvement de la Lune "). Pointing out that De- 

 launay's method has not yet received all the developments and 

 applications it is susceptible of, he next merely mentions Han- 

 sen's treatise on the perturbations of the small planets, and then 

 confines his attention to a careful examination of the labours of 

 Prof. Gylden and M. Poincare. He here enters into consider- 

 able detail, and closes with the remark that we owe much to M. 

 Poincare for his attack, "but the mist is not altogether dis- 

 pelled ; there is room for further investigation." This last 

 remark is made with reference to the Lindstedt series, which 

 "if convergent, would establish the non-existence of asymptotic 

 solutions" {cf. a paper by the same author in the January 

 number of the Bulletin, noticed in Nature, No. 1373, p. 382). 

 — A short note follows on Kronecker's linear relation among 

 minors of a symmetric determinant, by Prof. H. S. White. — Dr. 

 G. A. Miller's note on the lists of all the substitution groups 

 that can be formed with a given number of elements, is a valu- 

 able historical resume oi recent and past work in this subject. — 

 On Cauchy's theorem concerning complex integrals, by Prof. 

 M. Bocher, closes the mathematical papers. — From the Notes 

 we learn that Prof. White's paper was read before the Society. 



In the December number of the Botanical Gazette (vol. xx. ), 

 Mr. Frederick V. Coville, the Botanist of the U.S. Department 

 of Agriculture, contributes a very interesting account of the 

 botanical explorations of Dr. Thomas Coulter in Mexico and 

 'California, between the years 1824 and 1834. Among the chief 

 botanical explorers in North America during the first half of the 

 present century was Coulter. His collections were the basis of 

 important contributions to the descriptive botany of Mexico and 

 California. Born near Dundalk, Ireland, in 1793, he graduated 

 in the Dublin University in 1817, studied under De Candolle at 

 ^Geneva, and published his monograph of Dipsacere in 1824. He 

 was Keeper of the Herbarium of Trinity College, Dublin, from 

 1834 to 1843. This account is accompanied by a copy of the 

 principal part of the map published with Coulter's " Notes on 

 Upper California," and Mr. Coville adds that he hopes in the 

 near future to publish the letters of Coulter to A. Pyramus and 

 Alphonse De Candolle, of which, through the courtesy of Dr. 

 ■Casimir De Candolle, he has had copies. He further earnestly 

 begs for any additional facts relating to Coulter, which should be 

 sent to him to the Agricultural Department, Washington, U.S. 



VAnthropologie, Tome vi. No. 6. — Researches on the weight 

 of the brain among the lunatics at St. John's Hospital, Copen- 

 hagen, by F. Meyer and P. Heiberg. In these investigations, 

 which have extended over more than ten years, the authors have 

 excluded brains that have suffered great loss of substance, those 

 that have been the subjects of considerable cerebral haemorrhage, 

 and those that presented large tumours ; on the other hand, 

 brains suffering from oedema, anremia, hypersemia, atrophy, or 

 periencephalitis have been included. The mean weight of 398 

 brains of men was found to be 1320 grammes; the greatest 

 weight was 1866 grammes, and the least 995 grammes. 292 

 brains of women were examined; the mean weight was 1177 

 grammes, the heaviest weighed 1509 grammes, and the lightest 

 780 grammes. It appears that the brain gradually diminishes 



in weight after about fifty years of age. — On marriage amongst 

 the Polynesians of the Marquesas Islands, by Dr. Tautain. 

 Some of the marriage ceremonies described by the author clearly 

 point to a time, not very remote, when all the women were 

 common property, and marriage was unknown. A man on his 

 marriage acquires the right of a husband over all his wife's sisters, 

 and at the same time his brothers are entitled to exercise similar 

 privileges with respect to the newly-made bride. In the author's 

 opinion the Marquesans are a degraded people, and do not 

 deserve the least sympathy. — Prehistoric stations in (he neigh- 

 bourhood of Marseilles, by E. Fournier. In this paper are re- 

 corded the results of digging operations at no stations, 45 of 

 which have yielded evidence of the fauna and of prehistoric 

 industry. They may be arranged in four groups : (i) The 

 Magdalenian, (2) those belonging to the transition period, (3) 

 the Lower Neolithic, (4) the Upper Neolithic — Sculpture in 

 Europe before Grseco-Roman influence, by Salomon Reinach. 

 The author enters upon the last part of his inquiry, viz. the repre- 

 sentation of animals in primitive art, and the association of the 

 human form with the forms of animab. 



SOCIETIES AND ACADEMIES. 



London. 



Royal Society, March 5.—" On the Diurnal Periodicity of 

 Earthquakes." By Charles Davison, M.A. 



Reference is made to the previous work of De Montessus and 

 Omori, the former endeavouring to show that the diurnal 

 periodicity of earthquakes is apparent rather than real, and the 

 latter pointing out that a marked diurnal periodicity charac- 

 terises the after-shocks of great earthquakes in Japan. 



The results of twenty-six registers obtained by means of con- 

 tinuously recording instruments in Japan, the Philippine 

 Islands, and Italy are subjected to harmonic analysis with the 

 following conclusions : — 



(i) The reality of the diurnal variation of earthquake- 

 frequency seems to be proved by the approximate agreement in 

 epoch (mean local time) of the first four components (24, 12, 8, 

 and 6 hours) for the whole year at Tokio and Manila, and for 

 the winter and summer halves of the year at Tokio. 



(2) In ordinary earthquakes, there is in nearly every case a 

 marked diurnal period, the maximum generally occurring 

 between 10 a.m. and noon. The semi-diurnal period, though 

 less prominent, is also clearly marked, the maximum occurring 

 as a rule between 9 a.m. and noon and between 9 p.m. and 

 midnight. Other minor harmonic components are also occa- 

 sionally important, the first maximum of the eight-hour com- 

 ponent probably occurring about 6.30 a.m., and that of the 

 six-hour component about 3 or 4 a.m. ; but for these two 

 epochs the results are not always concordant. 



(3) Though the materials are insufficient for any general con- 

 clusion, the weaker shocks seem to be subject to a more marked 

 diurnal periodicity. 



(4) In the case of after-shocks of great earthquakes, the 

 diurnal periodicity is as a rule strongly pronounced. The 

 maximum of the diurnal period occurs within a few hours after 

 midnight, but the epochs of the other components are subject to 

 wide variation, possibly on account of the short intervals over 

 which the records extend. A special feature of after-shocks is 

 the prominence of the eight-hour and four-hour components. 



The epochs of the first four components representing the 

 diurnal variation of seismic frequency are compared in several 

 cases with those for barometric pressure and wind velocity. 

 While the variation of the former cannot be attributed exclusively 

 to either of the latter phenomena, it seems not improbable that 

 the diurnal periodicity of ordinary earthquakes may be due 

 chiefly to that of wind velocity, and the diurnal periodicity of 

 after-shocks chiefly to that of barometric pressure. 



Geological Society, February 26.— Dr. Henry Hicks, 

 F.R.S., President, in the chair. — On the structure of the 

 Plesiosaurian skull, by Charles W. Andrews. Owing to the 

 imperfection of the specimens described, various previous 

 accounts of the Plesiosaurian skull were incomplete, and 

 differed from one another in important particulars. There was 

 in the National Collection a fine skull of Plesiosaiirus macro- 

 cephalus which had lately been cleared from the matrix, with 

 a description of which the author was mainly occupied, though 

 other specimens, which were of assistance in clearing up some 



NO. 1378, VOL. 53] 



