i8o 



NATURE 



[December 26, 1895 



We have on our table several volumes published by learned 

 societies, but limits of space will not permit us to do more than 

 refer to them briefly. One of these volumes is the twenty-second 

 (new series) of the Proceedings of the American Association of 

 Arts and Sciences, and contains twenty-two papers read before 

 the Association between April 1894 and May 1895 '■> among 

 them being papers on the North American Centhophili, by Mr. 

 :S. H. Scudder ; nitro-paraffine salts, and bivalent carbon, by 

 J. U. Nef ; wave-lengths of electricity on iron wires, by Mr, 

 G. E. St. John ; the blastodermic vesicle of Stts scrofa domes- 

 ticus, by Mr. A. W. Weysse ; ternary mixtures, by Mr. W. D. 

 Bancroft ; a revision of the atomic weight of strontium, by Mr. 

 T. W. Richards ; and on the relation of hysteresis to tempera- 

 ture, by Messrs. F. A. Laws and H. E. Warren. Another 

 volume to which we can only briefly refer is the Atti d. Acca- 

 deinia d. Scienze Fisiche e MatemaHche of Naples (vol, ii second 

 series). In this we find memoirs on Italian Hymenoptera, by Prof. 

 A. Costa ; on certain Abelian equations, by Prof. V. Thollame ; 

 comparison of Right Ascensions simultaneously determined at 

 Capodimonte and Cordoba, by Prof. A. Nobile ; earth-currents, 

 by Prof. Palmieri ; Italian fossil ichthyology, by Prof. F. 

 Bassani ; and several others. We have also received a volume 

 of the Journal of Conchology, the first published under the 

 direction of the Conchological Society ; vol. xxvi. of the Pro- 

 ceedings of the Boston Society of Natural History (part iv. 1894- 

 95) ; and a number of maps from the Geological Survey of 

 Canada. One batch of these maps exhibits the principal auri- 

 ferous creeks in the Cariboo mining district, British Columbia ; 

 a second bundle refers to the geology of Guysborough, Anti- 

 gonish, and Pictou Counties, Nova Scotia ; while a third con- 

 tains a geological and topographical map of the southern part of 

 the lake of the Woods and Rainy River, Ontario, Eastern Town- 

 ships Map, Quebec, and a sheet showing the geological character 

 of South-west Nova Scotia. Finally, we have to acknowledge 

 the receipt of vol, v. part i. (second series) of the Proceedings of 

 the California Academy of Sciences, a volume of nearly eight 

 hundred pages filled with valuable papers on Californian natural 

 history ; and the second volume of " Beitrage zur Geophysik," 

 edited by Prof, Dr. G. Gerland. In this volume we find a 

 speculative paper on terrestrial magnetism, by Prof. A. Schmidt ; 

 a very long account and discussion of observations made with 

 the horizontal pendulum at Strassburg, during 1892-94, by the 

 late Dr. E. von Rebeur-Paschwitz ; an extensive collection of 

 observations of submarine earthquakes and eruptions, by Dr. E. 

 Rudolph ; and a critical study of the mean level of the solid 

 ■crust of the earth, of the land and water areas, and of the re- 

 lation between the land above sea-level and oceanic depressions, 

 by Dr. H. Wagner. 



OUR ASTRONOMICAL COLUMN. 



Orbits and Origin of Comets. — The investigations of 

 Schiaparelli led to the conclusion that comets moving in 

 parabolic orbits must have originally had a very small velocity 

 with respect to the sun, and that, apart from planetary perturba- 

 tions, the probability of elliptic orbits is very small. The latter 

 fact is demonstrated in a somewhat different way by M. V. 

 V^eWmaianiBttnetinAstronotnuiue, vol. xii. p. 515), the absolute 

 velocities of the sun and comets being introduced. This method 

 leads to the conclusion that the formation of hyperbolas is much 

 more probable than that of ellipses, and that ellipses of large 

 dimensions are much less probable than smaller ones ; further, 

 the supposed parabolic orbits which have been calculated are 

 probably nearly all hyberbolas. 



In conformity with the nebular hypothesis, M. Wellmann 

 regards the substance of which comets are formed as the debris 

 of nebulous matter not attached to any system in the process 

 of condensation, but in unstable equilibrium, and having nearly 

 the same proper movement as neighbouring centres of con- 

 •densation. Eventually assuming a hyperbolic orbit round a 



NO. 1365, VOL. 53] 



neighbouring sun, the "cosmic cloud" passes off" into space, 

 and may become attached to our system en route. 



M, Wellmann goes on to demonstrate that under the influence 

 of a solar electrical repulsion, elliptic orbits will approach the 

 parabolic form. Hence, in calculating the definitive orbits of 

 comets, this repulsion should not be lost sight of ; even neglect- 

 ing planetary perturbations, a comet may not move rigorously in 

 a conic section. Incases where calculation and observations are 

 discordant, it is suggested that a reconciliation be attempted by 

 supposing that the " constant of attraction " is itself variable, in 

 consequence of the varying electrical repulsion. M, Wellmann 

 also seems to be of opinion that this force of repulsion may be 

 found sufficient to explain the inequalities in the movement of 

 Mercury, which Leverrier ascribed to a possible intra-mercurial 

 planet ; the suggestion that the law of gravitation is not strictly 

 true (Nature, vol. li. p. 183), adds to the probability of this 

 explanation. 



Comet Brooks, 1895.— Attention is drawn by Dr. Deich- 

 miiller to a striking similarity between the elements of Comet 

 Brooks 1895 and those of the comet of 1652 (Ast. Nach., 3322) ; 

 this is shown by the following comparison, in which Kreutz's 

 elements for Comet Brooks are adopted : — 



Comet 1652. 

 1652 Nov. 13 



Comet Brooks. 

 = 1895 Oct. 21 



o) = 300° IO-6 \ 01 = 298° 13-0 



ft = 91 33"o [ 1895 a = 83 9-2 \ 1895 



2= 79 277 ) z= 75 22-" 



ij = 0-847 '/ = 0-839 



The continued ephemeris for the comet, following Dr. Ber- 

 berich, is as follows : — 



R.A. Decl. 



TBE MOVEMENTS OF HORIZONTAL 

 PENDULUMS. 



'T"'HE movements of horizontal pendulums referred to in this 

 -'■ note are those which have been observed in Japan and the 

 Isle of Wight. In reports to the British Association on the 

 earthquake and volcanic phenomena of Japan in the years 

 1883, 1884, 1885, 1887, 1888, 1892, 1893, and 1894, abstracts 

 are given of work which has been carried out in that country in 

 the investigation of earth tremors or pulsations, diurnal waves, 

 and other earth movements. The Report for 1892 describes a 

 pair of extremely light horizontal pendulums, the movements of 

 which, with the aid of mirrors and lenses, were recorded on 

 photographic plates and films, and gives some account of the 

 analysis of the resulting records. The observations were con- 

 tinued during the following year, when it was observed that the 

 direction of earthquake movement in many cases coincided with 

 the direction in which strata had been folded to form mountain 

 ranges bordering the Tokio plain. Another observation was that 

 certain earthquakes had been preceded by an abnormal amount 

 of tilting. During the last year, largely in consequence of the 

 liberality of the Royal Society of London, I have been able to 

 extend these observations, and records have been obtained from 

 horizontal pendulums, each provided with photographic record- 

 ing apparatns, from nineteen installations. The more important 

 of these installations were as follows. At Tokio in my house, 

 on a massive stone column. At a place 1000 feet distant, in an 

 underground chamber, excavated in the alluvium on a concrete 

 bed. At Kanagawa the observatory was in an artificial cave, 

 driven at a depth of about 50 feet in soft tuff" rock beneath its 

 junction with overlying alluvium. At Yokohama two instruments 

 were placed in a cave on the tuff rock, about two feet below its 

 junction with the alluvium. At Kamakura two instruments were 

 placed in a cave on hard tuff, which dips at an angle of 30° 

 north-east. 



These instruments were oriented so that their booms pointed 

 north-west or north-east, or parallel and at right angles to the 

 dip of the rocks. The localities mentioned are at distances from 

 Tokio of twenty, twenty-three, and about thirty-three miles. 



