J ULY 12, 1906] 



NA JURE 



253 



some of the principal opticians was a Beckley's anemometer 

 with Whipple's improvements, by which the direction of 

 the v:ine could be read at any time by pressing the electric 

 butlon of an indicator placed in any convenient room in 

 the observer's apartments. Another interesting feature was 

 soiTie carefully drawn diagrams illustrating the wind circula- 

 tion at the South Pole (results of the Vliscovary obs'tv 

 ations) for each month, both at Ihe surface and in the 

 higher regions of the atmosphere. Mr. Dines exhibited a 

 model of a kite and a meieorograph used for the investi- 

 gation of the upper air. 



The Physikalische Zeitschrift for June 15 contains a 

 description by Prof. Simon, illustrated by plans and photo- 

 graphs, of the new buildings and equipment of the insti- 

 tute for applied electricity in the University of Gottingcn. 

 .\ historical sketch is given of the steady development of 

 the teaching of electrolechnics at Gottingen during the 

 past twelve years, with particulars of the funds available 

 during this period and of the circuinstances which have 

 led to the creation of the new " institute." 



An attempt to ascertain the cause of the explosion which 

 sometimes occurs of sealed glass tubes containing radium 

 bromide is described by Mr. Paul L. Mercanton in No. 1 1 

 of the Physikalische Zeitschrift. Such an explosion might 

 possibly be due to the pressure set up within the tube by 

 some gas being gradually produced by the radium. A 

 glass tube containing 15 mg. of radium bromide, which 

 had been kept sealed during more than three years, was 

 accordingly opened under such conditions as would permit 

 of the measurement of any increase of pressure, and of the 

 examination of any gas liberated from the tube. It was 

 found, however, that no increase of pressure could be 

 observed, nor could the presence of helium be detected. 



The fourth edition of Prof. J. E. V. Boas's " Lehrbuch 

 dcr Zoologie fiir Studierende," which has just been pub- 

 lished by Mr. Gustav Fischer, Jena, contains much new 

 matter, both in the text and illustrations. There were 378 

 figures in the first German edition of this work, reviewed 

 in Nature of January 22, 1891 (vol. xliii., p. 268), and 

 this number has now been increased to 577 ; while both 

 the general and special parts of the text have been 

 thoroughly revised by the author, with the assistance of 

 Prof. J. W. Spengel, professor of zoology at Giessc. 



A SECOND edition, revised and enlarged, of Prof. C. 

 Moureu's "Notions fondamentales de Chimie organique " 

 has been published by Messrs. Gauthier-Villars, Paris. 

 The book is a synopsis of the facts and theories of organic 

 chemistry, and is intended to be an introduction to the 

 study of this science. 



OUR ASTRONOMICAL COLUMN. 



Finlay's Comet. — Writing to the editor of the .istrotw- 

 mische Nachrichten (No. 4102), Herr L. Schulhof 

 states that the Jupiter perturbations of Finlay's comet 

 bring the time of perihelion passage forward by about 

 twelve hours, thereby making it September 75 instead of 

 September 80 as eiven originally. The uncertainty of the 

 elements is probably not greater than a quarter of a day, 

 so that the perihelion time may now be taken as lying 

 between .September 7-25 and September 7-75. On Juiir- 

 this comet was twice as bright as w"hen discovered in 1886, 

 and its apparent brightness will steadily increase until the 

 end of August ; the observation of the comet is, therefore, 

 very probable. 



The Radiants of the Perseid Shower. — From a num- 

 ber of observations made at Dorpat during iqoi and iqo2, 

 M. Wwedenski, under the direction of Prof. Pokrowski, 



NO. 191 5, VOL. 74] 



has determined the following radiants of the Perseid 

 meteors : — 



Chief radiant point. 



a S 



40 ... + 57 

 47 - +58 

 47 ■■■ +56 

 43 ••• +60 

 35 ■■■ +55 

 .Another set of observations made on August 10 and 11. 

 1901, gave 40° 4-57° (24 meteors) and 44°-H57° (43 meteors) 

 respectively {Astronomische Nachrichten, No. 4098). 



Magnitude Observations of Nova Aquil^ No. 2. — 

 The magnitude of Nova Aquils No. 2 was observed at 

 the Bothkamp Observatory on seventy-seven occasions be- 

 tween September 5 and December 10, 1905, and the results 

 are given and discussed in No. 4098 of the .Istronomische 

 Nachrichten. On analysing these results, Dr. Guthnick 

 found that the curve showing the diminution of magnitudi- 

 was not a straight line, but a parabola of the following 

 form : — 



m = 10-96 + 0-0272/' - o •000095/-', 



where )ti = the Nova's magnitude at the time of observa- 

 tion, 1096 its magnitude on Septeinber 5, 1905, and ( the 

 number of days which elapsed between September 5 and the 

 lime of observation. The departure of the observed values 

 from those computed, for the same epoch, from the curve 

 are given in the table accompanying the results. 



.■\n Objective-Prism Comparison Spectrograph.— In 

 No. 5, vol. xxiii., of the Astrophysical Journal, Mr. de 

 Lisle Stewart, of the Cincinnati Observatory, proposes a 

 new form of objective-prism spectrograph which might be 

 employed for the determination of stellar radial velocities. 

 Instead of making two exposures with the one instrument, 

 as has been proposed in previous suggestions to this end, 

 Mr. Stewart proposes to employ two similar spectrographs 

 mounted rigidly on one equatorial mounting and having 

 the prism bases adjacent. This would bring the two 

 spectra of each star near together on the plate, and would, 

 presumably, eliminate, at least to some extent, the dif- 

 ferential effects of flexure and temperature changes. 

 Various details as to the inclination of the two tubes to 

 each other, the inclination of the plate, the positions of 

 auxiliary telescopes, &c., are given in the paper. Prof. 

 Frost estimates that the probable error of radial velocities 

 so determined would not be less than 20 km., but Mr. 

 Stewart suggests that practical experience would remove 

 the outstanding obstacles to more trustworthy determina- 

 tions. 



Russian Astronomical Observations.— We have recently 

 received five Bulletins of the St. Petersburg Imperial 

 Academy of Sciences, each of which contains one or more 

 papers of astronomical interest. Thus No. 5, vol. xvii. 

 (1902), includes a paper, in French, by Prof. Br(5dikhine 

 on the rdle of Jupiter in the formation of simple radiants, 

 and in vol. xviii. (1903) MM. Donitch and Jaegermann have 

 articles on the solar envelopes during the last minimum 

 and on the production of comets' tails respectively. Vol. 

 xix. (1903) contains several astronomical papers, including 

 one on the observations of the chromosphere outside 

 eclipses (M. Donitch), and another on comet forms (M. 

 Jaegermann). Vol. xx. (1904) is largely astronomical, and 

 includes articles on the Pulkowa spectrograph, the re- 

 pulsive force of the sun, the solar activity, and the Inter- 

 national Catalogue ; whilst vol. xxi. (1904) contains papers 

 by Prof. Belopolsky dealing with radial-velocity problems. 



.\ New Observatory for Hamburg. — From Himmel und 

 Erde (No. 8, 1906) we learn that a new observatory is 

 to be erected near Hamburg. The senate and council of 

 that town have voted one million marks towards its 

 erection and equipment. Among the other instruments 

 which it is proposed to instal in the new building, the 

 following are the chief ; — A meridian circle of 18 cm. 

 (7 inches) aperture, a 60 cm. (23 inches) refractor, a double 

 telescope for photographic purposes, and a reflector having 

 a mirror of i metre diameter. 



