6o 



NATURE 



[September 12, 1912 



North Atlantic is colder than usual, the centres of 

 depressions pass almost directly over the British Isles 

 and produce excessive cloudiness and rain. 



The Builder for August 30 has an illustrated article 

 on the reconstruction of the campanile of St. Mark's, 

 in Venice. Preserving the old foundations as a 

 nucleus, a strong enclosure of Istrian stone has been 

 constructed around them ; the old foundations had a 

 superficies of 222 square metres, and the present 

 foundations cover 407 square metres, nearly double the 

 surface. As the tower began to rise, a movable 

 framework was employed ; for the carrying up of the 

 materials a Steigler elevator was used, which also 

 lifted the bells into position. The bells weigh respec- 

 tively 3625, 2556, 1087, 1366, and ion kilograms, 

 and the angel 1300 kilograms. The tower 

 itself from outside the ground to its summit 

 weighs 8,900,000, and with its foundation included 

 about 12,970,000 kilograms. The Loggetta of Sanso- 

 vino has also been successfully restored. The loggia 

 had been completely crushed by the campanile in its 

 fall. All the fragments of sculpture were carefully 

 collected before commencing the work of reconstruc- 

 tion ; in the group of the Virgin and Child alone there 

 were no fewer than 1600 separate pieces. The new 

 campanile was opened on April 25 of this year. 



"Theories of Solutions," by Svante Arrhenius, 

 director of the Nobel Institute of the Royal Swedish 

 Academy of Science, Stockholm, is being published 

 this week by Mr. Frowde for the Yale University 

 Press. The volume constitutes the eighth of the series 

 of Silliman Memorial Lectures at Yale. 



OUR ASTRONOMICAL COLUMN. 

 Discovery of a Comet.— A telegram from the Kiel 

 Centralstelle announces the discoverv of a comet bv 

 Mr. Gale, of New South Wales, on September 9. The 

 position at 7h. 24-8m. (Sydney M.T.) on that date 

 was:— R.A. = i3h. 37m. is., decl. = 36° 31' 2" South. 



The Markings of Jupiter.— A valuable summary 

 of the phenomena attending the various prominent 

 markings on Jupiter is contributed bv Mr. Denning 

 to No. 452 of The Observatory. He 'first deals with 

 the large dusky marking discovered bv Major Moles- 

 worth, in the same latitude as the red spot, in 

 February, 1901. This remarkable object, which can 

 be seen well with a 3-in. refractor, has exhibited some 

 extraordinary variations in length, having, for 

 example, decreased from 115° in June, igii,"to 63° 

 recently. It has also exerted a marked influence on 

 the red spot, the motion of the latter being consider- 

 ably accelerated at the conjunctions of the two features 

 in 1902, 1904, 1906, 1908, and loio. For the period 

 1894-1910 the rate of rotation of the red spot was 

 qh. 5sm. 40-63S., exactly that adopted for system ii., 

 but then a rapid acceleration set in, and for the two 

 succeeding years the period was gh. 55m. 37"5s. This 

 drifting westward was at the rate of about 22,000 

 miles per year, but recent observations indicate that 

 it is temporarily suspended. 



Observations of Nova Geminorum No. 2.— .\ 



number of observations of Nova Geminorum No. 2 



are discussed in No. 4598 of the Astronomische Nach- 



richten, chiefly dealing with determinations of position 



NO. 2237, VOL. 90] 



and magnitude. Dr. H. E. Lau, from observations 

 made between March 14 and May 18, finds secondary 

 maxima on the light-curve on March 14, 23, and 31, 

 April 18, and May i. At first the period appeared 

 to be about eight days and the amplitude I'o magni- 

 tude, but later the period lengthened and the ampli- 

 tude decidedly decreased. Most of the observations 

 indicate that the magnitude became fairly stationary 

 about the end of May, its value being about 80, but 

 Prof. Eginitis records an apparent augmentation from 

 8'o on June 4 to 7*4 on June 7. 



Prof. Newall states that spectroscopic observations 

 by Messrs. .Stratton and Brunt on August 13 showed 

 the nebula line, soimm, to be much the strongest line 

 in the visible spectrum ; other lines observed were at 

 XX464 (?), 486 (H^), 496, 531 (?), and 575. The mag- 

 nitude, difficult to estimate, was probably a little 

 brighter than g'o. 



Prof. Strbmgren records the magnitude as 7'7o, on 

 the PD system, on August 24, while, in No. 452 of 

 The Observatory, Mr. Harold Thomson gives it as 

 7'7 on August 20, on the scale employed by the 

 Variable Star Section of the B.A.A. 



The Orbit of $ Persei. — The star $ Persei is one 

 of those interesting binaries in which the radial 

 velocity as determined from the H and K lines of 

 calcium differs from that determined from the other 

 lines. Its spectrum is of the Oe 5 B class, according 

 to Miss Cannon, and shows lines of H, He, Ca, and 

 Fe, but the H and He lines are generally too diffuse 

 to give trustworthy results for the velocity. 



Using the H and K lines only, Mr. Cannon, of tbft 

 Ottawa Observatory, has derived an orbit from his 

 own measures and those made at the Yerkes Observa- 

 tory, which he publishes in No. 3, vol. vi., of the 

 Journal of the R.A.S., Canada. He finds the period 

 to be 6'93i days, the range of velocity i5'7 km., and 

 the velocity of the system 15-4 km. The diameter of 

 the projected semi-major axis of the orbit is 751,800 

 km. An attempt was also made to determine the 

 velocity from the broad lines, other than calcium, but 

 nothing more definite can be said than that they show 

 a much higher positive velocity than do the H and K 

 lines. 



C.walogue of Stellar Parallaxes. — No. 24 of the 

 Publications of the Astronomical Laboratory at 

 Groningen contains a wealth of information concern- 

 ing the parallaxes, probable intrinsic luminosities, 

 &c., of 365 stars. The table has been made up from 

 many sources, and relative weights are given to the 

 different values. There are eleven stars with parallaxes 

 greater than +o'3oo", the five nearest, with their 

 adopted parallaxes, being: a Centauri ( + o'759"), 

 Sirius ( + o'376"), Piazzi, oh. 130 (4-o'36o"), t Ceti 

 ( + o'334"), and Procyon (-)-o'324"). Ten stars have 

 computed luminosities greater than one hundred times 

 that of the sun, the five most luminous being : 

 3 Centauri (520), Regulus , (423), Achernar (350), 

 Capella (300), and Arcturus (230) ; the values in 

 brackets are the computed luminosities, that of the 

 sun being taken as unity. 



The Orbits of Comets.— In No. 4598 of the .4stro- 

 nomische Nachrichten, Prof. Stromgren points out, in 

 reference to a recent note by Prof. W. Pickering on 

 the fundamental form of cometary orbits, that Prof. 

 Pickering has misconstrued the sense of his conclu- 

 sions. The final contention of Prof. Stromgren 's (not 

 Prof. Kobold's, as was inadvertently stated in our 

 previous note on August 15) was that if the effects 

 of Newtonian gravitation be strictly taken into con- 

 sideration it is probable that all the comotary orbits 

 yet considered would prove to be elliptical. 



