May 6, 1897] 



NATURE 



stimulating and destructive agents ; earth currents recorded at 

 the Vesuvius Observatory in 1895, ^"d the history of Vesuvius 

 from 1875 to 1895 ; a mathematical investigation of the lines of 

 nodes of vibrating membranes ; the geology of the Southern 

 Appennines (this elaborate paper occupies 128 pages); the 

 alternate current transformer with a condenser in the secondary 

 circuit ; the physical constitution of the atmosphere, from the 

 results of observations made during eight balloon ascents by 

 James Glaisher, also a new formula for the calculation of 

 altitude from barometric observations. — In the Kendiconti del 

 Reale Jstittito LoiiibarJo, Prof. Luigi de Marchi gives a mathe- 

 matical investigation of the effect of viscosity on the movements 

 of glaciers. 



Now that acetylene can be readily prepared in the laboratory, 

 many new uses will no doubt be found for it. The most recent 

 proposal in this connection is that made by H. G. Sdderbaum, 

 in the current number of the Berichte. It appears that the gas 

 can be employed for the quantitative precipitation of copper in 

 ammoniacal solution, and for its separation from metals like zinc, 

 which are not precipitated by ammonia. Acetylene possesses 

 the great advantage over sulphuretted hydrogen, which is usually 

 employed for this purpose, that it yields a precipitate which can 

 be filtered and washed very rapidly, and which does not easily 

 l)ecome oxidised and pass into solution. The washed precipitate 

 is finally decomposed by dilute nitric acid, the solution filtered 

 and evaporated to dryness, and the residue ignited and weighed 

 as oxide. 



The additions to the Zoological Society's Gardens during the 

 past week include an Orang-outang (Siinia satyrus, i ) from 

 Borneo, presented by Captain Francis R. Pelly, R N., H.M.S. 

 Porpoise ; a Bonnet Monkey [Macacus sinicus, S ) from India, 

 presented by Mrs. Douglas ; a Rhesus Monkey {A/acacus rhesus, 

 i ) from India, presented by Mr. P. A. Ledger ; a Mongoose 

 Lemur {Lemur iiioiigoz) from Madagascar, presented by Mr. P. 

 Baxter ; a Grey Ichneumon {Herpesles griseus) from Ceylon, 

 presented by Surgeon- Major C. Seymour ; a Chimpanzee 

 {Anthropopithecus troglodytes, ? ), a Black Gallinule {Liiiinocorax 

 iiiger) from West Africa, presented by H.E. Colonel F. Cardew, 

 C.M.G. ; two Himalaya Goldfinches (Carduelis caniceps, <J 9 ) 

 from India, presented by Mr. Frank Finn ; two Egyptian 

 Cteeae {C/ienalopex cegyptiaciiSy i 9) from Africa, presented by 

 Mr. A. E. Speer ; a Mange's Dasyure {Dasyurus viverrinus) 

 from Australia, presented by Mr. J. C. Chipper ; a Peacock 

 V\\tz.?,2i.n\. {Polyplectron chinquis, i){xom British Burmah, pre- 

 sented by Mr. Charlton Parr; a Burrhel Wild Sheep {Ovis 

 urrltel,<i) from the Himalayas, a Reed Buck {Cervicapra 

 •nindinum, i ) from the Limpopo River, South-east Africa, a 

 Sing-Sing Water Buck {Cobus unctiiosus, S ) from West Africa, 

 I Somali Wild Ass {Equus soiniltctis, (J ), a Somali Ostrich 

 ^Strtithw molybdophanes,^) from Somaliland, six Pintails 

 Dafila acuta, 3<j, 39), European; two Smith's Partridge 

 lironze-winged Pigeons {Geopkaps stitithi,^ 9) from Australia, 

 I wo White-headed Woodpeckers {Leucouerpes candidus) from 

 Brazil, two Wreathed Hornbills {Rhytidoceros undulatus) from 

 Borneo, a Silky Cow Bird {Molothrus bonariensis) from South 

 America, purchased. 



OUR ASTRONOMICAL COLUMN. 

 A Remarkable Rei.atio.v between the Distances, 

 Masses, and Surface Gravities of the Planets.— In 

 he Bulletin Astronomique for April, M. P. Berthot describes an 

 ingenious empirical law which approximately connects the mean 

 radii (R) of the orbits, the masses (///), and the values of ^ at the 

 equators of the different planets. By employing a graphical 

 method in which the abscissa: represent the values of gravity (/), 



and the ordinates those of - , all the planets, with the excep- 

 in 



NO. 1436, VOL. 56] 



tion of Mercury, fall very approximately on an ellipse, '^ being 



considered negative for all values of/ greater or equal to i, and 

 the unit value of/ being that at the surface of the earth. 



If -, instead of/, be used as the abscissae, the ellipse becomes 



then an equilateral hyperbola, and if the logarithm of - be substi- 

 tuted, the same becomes a parabola. The following table gives 

 the true and calculated values of / for one of the three curves, 

 namely, the ellipse, computed by M. Berthot, those for the 

 hyperbola and parabola showing somewhat greater errors per 

 cent, in the case of Mercury. These latter are not referred to 

 below. 



? /(true). f\f^''^"> Error 



;// r \ I ellipse. for loo. 



Mercury ... 6*350 ... 0-439 ... 0-502 ... 14-3 



Venus 0-919 ... 0802 ... 0-803 •■• O'l 



Earth 1000 ... i-ooo ... I'ooo ... o-o 



Mars 14-510 ... 0-376 ... 0-375 ... 0-3 



Jupiter ... 0-017 ••• 2-261 ... 2-284 ■•• I'O 



Saturn 0103 ... 0-892 ... 0877 ••• 17 



Uranus ... 1-414 ... 0-754 ... 0-764 .. 1-3 



Neptune ... r 824 ... 1-142 ... 1-120 ... 2-0 



To make Mercury conform with the values calculated by the 

 above-mentioned formulce, it is suggested that either the old 

 value of the mass determined by Le Verrier (0-0715) must be 

 adhered to (contrary to more recent investigations), or, if the 



mass be retained, the diameter of the planet must be 



9,700,000 ^ 



assumed to be one-quarter too large by the phenomenon of 

 irradiation. 



The Double Star 44 Bootis.— This star, which was dis- 

 covered on August 17, 1781, by Herschel, has recently {Monthly 

 Notices, vol. Ivii. No. 5) been pointed out by Mr. Burnham in 

 consequence of the singular and remarkable arrest of the relative 

 motion of the two stars. For a period of thirty years these stars 

 gradually increased their distance from one another at a nearly 

 uniform rate, the position angle at the .same time slowly ad- 

 vancing. After this, for a period of equal length, the motion 

 had apparently been arrested, and "down to the present time, 

 they have remained absolutely at rest, so far as one can tell from 

 full and careful sets of measures by the best double-star ob- 

 servers." This is a remarkable system, which evidently is 

 unique among the known binaries, and, as Mr. Burnham points 

 out, it is not easy to account for such a state of affairs. He 

 remarks, however, that the usual dark-body hypothesis will 

 readily suggest itself ; and it is easy to imagine one of these 

 stars with an invisible companion, both moving in a very eccen- 

 tric orbit in a plane parallel to the line of sight, and to select a 

 period and direction of motion that will not only explain the 

 motion, but the absence of motion shown by the observations 

 of the visible components, and " when this is presented with 

 the usual refinements of computation, doubtless for the time 

 being a plausible case could be made out." It will be interest 

 ing to watch this binary, and see, when the relative motion has 

 been resumed and a decided change of position has taken place, 

 whether an accurate, or even approximate, orbit can be obtained. 

 The case is decidedly a unique one for double-star observers ; 

 and as there seems to be no question about the observations 

 themselves, the steady change of position and subsequent arrest 

 being based on "unimpeachable observations by the best 

 observers," special interest will be attached to future measure- 

 ments. 



Rei'Ort of Mr. Tebbutt's Observatory.— The energetic 

 proprietor of this observatory presents a most satisfactory report 

 for the year 1896, the amount of work accomplished being 

 unusually large, owing to the very great number of clear nights 

 experienced. The meridian work consisted chiefly in observ- 

 ing stars with the 3-inch transit instrument for checking the 

 sidereal chronometer, which was used as timekeeper throughout 

 the year. The observations of occultations of stars by the moon, 

 made with the 8-inch equatorial, are stated to be the richest 

 obtained in any one year since the foundation of the observatory. 

 Other observations included 810 comparisons of minor planets 

 with the filar micrometer, the phenomena of Jupiter's satellites, 

 double and variable stars, and the regular meteorological work. 

 The report states that all the astronomical and nearly all the 

 meteorological observations were made by Mr. Tebbutt himself. 



