October 31, 1907] 



NA TURE 



671 



Mr. W. Ernest Cooke, Government astronomer at the 

 Perth Observatory, West Australia, directs our attention 

 to an exhibition of globe lightning, or a fireball of some 

 sort, which was noticed by two observers on September 7. 

 Mr. Cooke did not himself see the display, but he can 

 certify that about the time mentioned by the observers 

 there was a blinding flash of lightning in the viciniiy, 

 followed almost immediately by a heavy crash of thunder. 

 The observers who reported the matter to Mr. Cooke are 

 stated by the Daily News of West .Australia (September q) 

 to have described their experience as follows : — In ihc 

 middle of the reverberation of the thunder a tremendous 

 explosion about 6 feet from the ground was heard, and 

 a momentary flash of blinding intensity was seen. Both 

 saw a lurid red ball, estimated by them as about 4 inches 

 in diameter with a circle of bright yellow flame, with a 

 diameter which seemed to be 18 inches, which graduated 

 in colour until it faded at the edges. .\s there are only 

 a few authenticated instances of similar displays, it is 

 desirable to place each new instance on record. 



Messrs. George Philip and Son, Ltd., have sent us a 

 specimen of their " New Standard Time Dial " designed 

 by Prof. R. A. Gregory for the determination of the local 

 mean time at any place on the earth's surface, corre- 

 sponding to the time at the place where the dial is being 

 used. This simple and useful device consists of a stout 

 wooden board on each side of which is printed a clock 

 face showing the hours from noon to midnight and mid- 

 night to noon. Within each dial is a rotating disc on 

 which is printed, on the one side, a map of the northern, 

 and on the reverse side a map of the southern, hemisphere. 

 Meridians of longitude are drawn at intervals of 15° on 

 each map, and where a meridian marks a commonly used 

 standard time, such as Greenwich, mid-Europe, or inter- 

 Colonial, it is so designated ; the meridian where the date 

 changes from the American to the Asiatic date is also 

 marked. By simply rotating the inner disc until the 

 meridian of a place is opposite to the actual time, as 

 shown on the dial, the corresponding local time at any 

 other place may be read off directly. The device will be 

 found serviceable; and its low price (3s. 6d. net) should 

 ensure its appearance in all places, especially schools, 

 where the longitude-time problem has to be solved 

 frequently. 



Le Radium for September contains an important article 

 by M. Jean Becquercl on the influence of temperature on 

 the absorption of solids. It appears from M. Becquerel's 

 researches that increase of temperature of a solid dis- 

 places the absorption bands towards the red end of the 

 spectrum by two or three units of the fifth figure of the 

 wave-length per 100° C, while the bands at the same 

 time increase in width and change in intensity, the width 

 being proportional to the square root of the absolute 

 temperature. 



The communication to the Physical Society of Berlin 

 in which Dr. E. Goldstein announced his discovery of the 

 existence of two independent spectra of each of the 

 elements caesium, rubidium, and potassium has been re- 

 produced in full in the Physikalische Zeitschrift for 

 October 15. The new spectra are produced by powerful 

 condenser discharges, and have not a single line in 

 common with the old, or as Dr. Goldstein names them, 

 the arc spectra. The new lines do not appear to fall into 

 series, and the author suggests that they constitute the 

 " fundamental spectra " of these elements, the arc spectra 

 being due to polymerisation in the metal vapour, which 

 is impossible in the powerful sparks necessary to produce 

 the former. 



NO. 1983, VOL. 76] 



In the June number of Terrestrial Magneiisin and 

 Atmospheric Electricity, Mr. Y. Homma calculates the 

 rates of change of the electrical potential at different 

 distances above the earth's surface on various assump- 

 tions as to the distribution of positive charges in the 

 atmosphere, the earth being taken as a sphere. None of 

 the calculated rates of change agrees with the somewhat 

 meagre observations which have been made, and the 

 author points out the importance of further work in this 

 direction. 



In the report of the third Prehistoric Congress of France 

 in Nature of October 24 reference was made to some 

 photographs of Japanese megaliths, which were said to 

 have been taken by M. Goodhan (p. 649, col. 2, line 3), 

 Prof. W. Gowland writes to say that the photographs 

 were taken by him, and were lent to Mr. F. \'. Dickins 

 for exhibition at the conference. The name was printed 

 exactly as it was given by the secretary of the conference, 

 who furnished the report of which a translation appeared 

 in Nature. 



OUR ASTRONOMICAL COLUMN. 



Astronomical Occurrences in Novemker :— 



Nov. 4. I5h. 33m. to igh. 14m. Transit of Jupiter's Sat. 



III. (Ganymede). 



10. Saturn's major axis outer ring = 43""oo, minor axis = 



o"64. 



12. 4h. iim. Moon in conjunction with Mars. (Mars 



o°58'S.) 



,^' ",,' ;''"■ [-Transit of Mercury across the Sun. 

 14. ih 47m. J ' 



,, loh. 24m. Moon in conjunction with Saturn. 



(Saturn 2° 26' N. ) 

 14-16. Epoch of the Leonid meteors. (Radiant i5o°-h 



22°.) 

 17. loh. im. Minimum of Algol (;8 Persei). 



20. 6h. 50m. Minimum of Algol (/8 Persei). 



,, 4h. 25m. to 5h. 4m. Occultalion of 5' Tauii (mag. 



3"9'- 

 ,, 4h. 44m. to 5h. 35m. Occultation of S'-* Tauri (mag. 



4-7). 



21. I7h. 6ni. to I7h. 54m. Occultation of f Tauri (mag. 



ro). 

 23. I5h. 41m. to I7h. Im. Occultation of 5 Geminorum 



(mag. 36). 

 25. 2oh. 34m. Moon in conjunction with Jupiter. 



(Jupiter I°57'S.) 

 29-30. Mercury rises 2h. 2m. before the Sun. 

 30. l8h. 49m. to 23h. 39m. Transit of Jupiter's Sat. IV. 



(Callisto). 



Comet Mellism, 1907c. — Three observations of Mellish's 

 new comet are reported in No. 4207 of the Astroiiomische 

 Nachrichten (p. in, October 17). Prof. Hartwig's observ- 

 ation on October 15 showed that the comet was round, 

 with a diameter of 3' and a central condensation. The 

 magnitude at I5h. 52m. on October 15, as estimated by 

 Prof. Becker at Strassburg, was 9-3. 



The Transit of Mercury. — In view of the approaching 

 transit of Mercury (November 14), Mr. W. T. Lynn pub- 

 lishes a letter in No. 388 of the Observatory (p. 382, 

 October) in which he directs attention to earlier observ- 

 ations of this phenomenon and to its periodicity. He 

 states that the first authentic observation of the transit 

 was made in 163 1 by Gassendi, and was followed by an 

 observation by Jeremiah Shakerly, an Englishman who 

 went to Surat, India, in 165 1, for the purpose of observing 

 the transit. Halley observed the 1677 transit at St. 

 Helena, and this led him to suggest that transits of Venus 

 would afford a peculiarly advantageous means of deter- 

 mining the solar parallax, a suggestion that was first 

 carried out officially in 1761. 



Mr. Lynn also directs attention to the peculiar com- 

 mensurability existing between the orbital periods of the 

 earth and Mercury, the former completing forty-six in 



