66 



A^A TURE 



[May i8, 1905 



V. \'. Lavroff, followed by a full bibliographical index. — 

 Determination of the inner energy of the gas-liquid 

 systems, by A. N. Tschoukareff, with a resume in French. 

 By sealing various liquids in steel " sparklets," capable 

 of supporting considerable inner pressures, the author 

 could thus bring these liquids to high temperatures, above 

 the critical temperature, and thus determine the specific 

 heat of these substances in the critical state. — On the 

 theorv of the singing Voltaic arc, a mathematical inquiry 

 bv S. Maysel, which brings the author to conclusions 

 opposed to those of Duddell, Janet, and Granqvist. 



Messrs. M..\cmill.\n .\nd Bowes, Cambridge, will pub- 

 lish in a few days a small book on " Mendelism," by Mr. 

 R. C. Punnett, Cambridge. The volume will give an out- 

 line of Mendel's work on heredity, and its recent develop- 

 ments. 



In the notice of Dr. D. Murray's volumes on 

 " Museums " in our issue of .\pril 13 (p. 554), the reviewer 

 referred to the list of museums in the United Kingdom 

 given in the work as being based on one prepared by the 

 Museums Association. Mr. E. Howarth writes to point 

 out that the list was a reprint of one prepared by a com- 

 mittee of the British .Association in 1887, and not by the 

 Museums Association, which did not commence the pre- 

 paration of a museums directory until 1902. 



Messrs. George Bei.l .\Nn Sons have published the 

 second part of the key lo the " Elementary -\Igebra " of 

 Messrs. W. .M. Bak.-r and A. A. Bourne. 



OUR ASTRONOMICAL COLUMN. 



Orhit of CoMEi 1905 11. — A graphical repre!>entation of 

 the orbit of comet 1905 a, according to the elements com- 

 puted bv Miss I^amson, of the U.S. Naval Observatory, 

 is given in No. 5, vol. xlii., of Popular Astrouowy. From 

 this it is seen that the comet, at its perihelion, passed 

 within 12,000,000 miles of the earth, but the latter body 

 had, about a month before, passed the point where closest 

 proximity was possible. The comet will continue, there- 

 fore, to grew fainter, and on May 30, according to Miss 

 Lamson's ephemeris, it will be only 0-3 as bright as when 

 first disccver.'d, and it was only' a faint telescopic object 

 then. 



Provisional Elements for Jltiter's Sixth Satellite. 

 — Whilst aw'aiting more definite information from Eick, 

 Mr. Crommelin has computed provisional elements for 

 Jupiter's sixth satellite from the data already available. 

 These data are not sutlicient to decide the eccentricity of 

 the orbit, so a circular form has been assumed. Although 

 the Lick observers have now stated definitely that the 

 " retrograde " in their first telegram did not refer to the 

 orbital motion, the observations yet made have not settled 

 the question of direction, and Mr. Crommelin has therefore 

 computed elements both for "direct" and "retrograde." 

 He finds the distance from the parent planet to be about 

 6,200,000 mi^les, and a comparison of this with the observ- 

 ational data favours a " direct " orbital motion, although, 

 of course, much uncertainty exists. The inclination of the 

 satellite's to the planet's orbit is 23°-8 or 23°-9, according 

 to whether the motion is " direct " or " retrograde," whilst 

 the inclination of the orbit to Jupiter's equator is either 

 26° or 24°-/. This inclination is unusually large as com- 

 pared with other satellite orbits in the solar system, and 

 according to the reports so far received the orbit of the 

 seventh satellite has a still larger inclination. 



.According to the " direct " hypothesis, the pole of the 

 sixth satellite's orbit is only about i°-5 from our own 

 North Pole, so that the major axis will always point nearly 

 due east and west. .\ determination of the position angle 

 next July, when it again reaches western elongation, should 

 decide the question of the satellite's motion. The semi- 

 minor axis of the apparent ellipse on December 25 (W. 



NO. 1855, VOL. 72] 



elongation) was 4'-96, and from this it is deduced that the 

 inclination of the orbit plane to the line of sight on that 

 date was 5°-7 {Monthly Notices, vol. Ixv., No. 5). 



Winter Fireballs in 1905. — In No. 357 of the Observ- 

 atory Mr. Denning summarises the accounts of fireball 

 observations, during January and February, which have 

 been forwarded to him. Quite an unusually large number 

 of these objects were observed. One slow meteor seen on 

 January 27 at iih. 59m., and another seen on February 

 28d. I2h. lom., were at least as bright as the full moon, 

 whilst one on January 14 at loh. i6m., which was brighter 

 than Venus, was noted by one observer as being followed 

 by a slight rumbling noise at an interval of 25 minutes- 

 The probable radiant of this object was 119° 4- 3°, and it 

 travelled from a height of 60 miles to a height of 29 miles, 

 along a path of about 55 miles, with a velocity of 15 miles 

 per second. .A. meteor seen at loh. 15m. on February 28 

 from a radiant at 220° 4- 40° divided into two parts at dis- 

 appearance, whilst the last named of the eighteen objects 

 mentioned in Mr. Denning's report, seen at gh. lom. on 

 March 18, swelled out and exploded three times with 

 lightning-like flashes during its four seconds' flight. 



Observ.4TIONS and Light-curves of .Several Variable 

 .Stars. — In No. 401 1 of the Astrononiische Naclirichtcn 

 Dr. L. Terkan, of the O-Gyalla Observatory, publishes the 

 results of a series of observations, and some light-curves, 

 of several important variable stars. The observations were 

 made during 1904 with a Zollner photometer, and the 

 results are compared with the various published elements 

 of each object. The stars dealt with are S .Sagitta", 

 T N'ulpecula;, 6 Cephei, 77 Aquil^e, /3 Persei, and A Tauri. 

 Observations of " D, " in the Solar Spectrum. — In 

 No. 4012 of the Astrononiische Nachrichtcn Dr. H. 

 Kreuslcr, of Berlin, records two observations in which he 

 saw the helium line, D,, as a dark line in the spectrum of 

 the region about a sun-spot. The first observation was 

 made between noon and 2 p.m. on June 12, 1904, the 

 second on the following day, and on both days the facuUc 

 surrounding the spot were exceptionally bright. Dr. 

 Kreusler suggests that, as it was near a maximum epoch 

 of solar activity when Prof. Young recorded a similar 

 observation in 1870, this phenomenon may be a character- 

 istic of sun-spot maxima. 



Brightness of Jupiter's Satellites. — In an attempt to 

 settle the question of the variability of Jupiter's four 

 brightest satellites, Prof. Wendell, of Harvard, made a 

 series of photometric comparisons of them with a polar- 

 ising photometer attached to the 15-inch telescope. The 

 satellites w'ere compared, for brightness, among themselves, 

 and a large number of " settings " was made in such a 

 manner as to eliminate accidental errors. The order of 

 brightness was always iii., i., ii., iv., and the results afford 

 no evidence for any variability during the period over 

 which the observations extended, viz. from J.D. 241691111 

 to J.D. 241692S (Circular No. 95 of the Harvard Collei;!- 

 Observatory). 



Vari.\ule Stars in the Small Magellanic Cloud. — 

 Some time ago it was reported in these columns that Miss 

 Leavitt had newly discovered 57 variable stars in the 

 small Magellanic cloud. In order to provide material for 

 a closer study of the light-curves of these objects, sixteen 

 negatives were taken at Arequipa with the 24-inch Bruci 

 telescope, with exposures varying from two to four hour^ 

 each. When the plates arrived at Cambridge (U.S. .A.) in 

 January, .Miss Leavitt was greatly surprised to find that 

 in this same region there were hundreds of variables which 

 had not been seen on the previous inferior plates. In 

 Circular No. 90 of the Harvard College Observatory the 

 number in each half-degree square of the region is given, 

 and, including the 57 previously announced, there are 910 

 new variable stars in all. Tliis means that within the 

 limits of the clouds there is one variable to every 308 stars, 

 whereas of the 40,000 stars in the surrounding region 

 shown on the plates only" one in 3300 is apparently a 

 variable, although all have been examined with equal care. 

 During the examination of the plates it was found that 

 a thirteenth magnitude star, the position of which for 

 1900.0 was R..A. = ih. 6m. is., dec. = —72° 45'i;, has a 

 large proper motion amounting to -|-o-i3s. in R..A., 

 -|-o"-42 in dec, and o"-73 in a great circle. 



