July 4, 1907] 



NA TURE 



229 



divisible by 2, 3, 5, or 7. For this purpose the number in 

 C|UPSlion is first expressed in the form m. 20580 + (q 2-10 + r). 

 The tables headed with the numbers (Tablettes grilles) have 

 slots cut in them which are placed over the columns headed 

 with the columns r, and by following certain rules accord- 

 ing to the sign in the above form, and noticing whether the 

 figures (" cotes ") in the subsequent lines of the columns 

 are in dark or light type (" cotes grasses " or " cotes 

 maigres "), it is possible to ascertain which of the prime 

 numbers in the next adjoining column of the open tables 

 are factors of the original number. We have verified the 

 method, but the rules are a little difficult to apply at first. 

 The tables are published by Gauthier-Villars, of Paris. 



Kkff.rring to our note on the scientific uses of the 

 kinematograph (Nature, May 23, p. 87), Mr. \V. F. 

 Cooper, of Water Lane, Watford, writes pointing out the 

 difficulties experienced by amateurs in obtaining sufficiently 

 rapid films for the purposes of research. The fastest films 

 he has been able to obtain have a speed of H. and D. 

 100, less than half that of ordinary snapshot plates. This 

 speed is quite inadequate for the photography of operations, 

 for in a case observed by Mr. Cooper an exposure of ten 

 minutes would have been required. Mr. Cooper has been 

 successful in recording the movements of blood corpuscle 

 parasites, but the chief obstacle in the way of further 

 progress is lack of general interest in the uses of the 

 kinematograph on the part of scientific workers as opposed 

 to professionals. He invites correspondence with others 

 who have taken up this line of work with the view of 

 producing a demand for films better suited to the purpose 

 in the matter of speed and orthochromatic properties. 



A SIMPLE lecture experiment to demonstrate the trans- 

 formation of yellow phosphorus into the red variety is 

 described by F. Zecchini in the Gazzetta (vol. xxxvii., i., 

 p. 422). Ordinary dry phosphorus is melted in a glass 

 tube 30 cm. long and 7-8 mm. in diameter by surround- 

 ing the tube with a bath of concentrated sulphuric acid 

 the temperature of which is gradually raised to iSo°. 

 Sufficient phosphorus should be used to give about 10 c.c. 

 of liquid. When the whole has melted, a minute crystal 

 of iodine is added ; as the crystal falls through the molten 

 mass the immediate transformation of the latter into red 

 phosphorus becomes clearly visible. 



Messrs. R. and J. Beck, Ltd., have published a 

 pamphlet by Captain Owen Wheeler on " Telephotography 

 .Simplified for Naval, Military, and General Purposes." 

 '1 he price of the pamphlet is is. 3d. 



OUR ASTRONOMICAL COLUMN. 

 Comet igoyd (Daniel). — The daily ephemeris computed 

 bv Dr. E. Stromgren for comet 19071! is given up to 

 July 10 in No. 4185 of the Astronomische Nachrichtcn 

 (p. 155, June 21). The following is an extract there- 

 from : — 



Ephemens i2h. (M.T. BerUii). 

 11,07 oi(lrue) «(lrue) Brlghtmss 



July 4 ... I 4-3 



„ 6 ... 1112 



„ 8 ... 1 i8-3 



,, 10 ... I 25-5 



+ s 00 

 + 5 31'' 



-1-6 2-1 



+ 6 329 



2-17 



An observation at Strassburg on June 17 gave correc- 

 tions of -I-4S. and -|-o'-4, and the magnitude was estimated 

 as 8-5 or 90. On that date the brightness, according to 

 the ephemeris, was about 11. The apparent path as 

 shown in the above ephemeris lies roughly between So and 

 fi Piscium, and the comet now rises shortly after mid- 



night. 



NO. T966, VOL. 76] 



Peculiar Spectrum of € Capricorni. — .■^ note by Mr. 

 V. M. Slipher, of the Lowell Observatory, on the spectrum 

 of € Capricorni (magnitude = 4-5) appears in No. 4, vol. 

 XXV. (p. 285, May), of the Astropliysical Journal. Spectro- 

 grams taken last autumn showed bright lines, and more 

 recent ones show that the hydrogen lines are paired — a 

 dense dark line with a weak bright line above it. The 

 dark hydrogen and the metallic lines indicate a radial 

 velocity of about 45 kilometres for October 8, but on 

 October 27 this had decreased to 35 kilometres, the lines 

 being displaced towards the red. Broad and diffuse helium 

 absorption lines are also shown, but do not participate in 

 the displacement towards the red ; in fact, measures of 

 some of the sharper ones show a slight " shift " towards 

 the violet, and it therefore seems possible that these, with 

 the bright hydrogen lines, belong to one member of the 

 system, whilst the dark hydrogen and the metallic lines 

 belong to the second. 



Atmospheric Currents in Celestial Bodies. — A paper 

 on the causes which produce different currents in the 

 atmospheres of celestial bodies, such as Jupiter and Saturn, 

 is published bv Senor Jose Comas Sola in No. 4185 (p. 145, 

 June 21) of the Astro}iomisclie Nachrichtcn. Senor Sola 

 calls in the tide-raising effects of very small satellites 

 revolving in close proximity to the primary to account 

 for these atmospheric currents. Taking Jupiler as an 

 example, these hvpothetical satellites produce an acceler- 

 ating effect in the superficial layers of the atmosphere near 

 to the equator. The larger, more distant satellites produce 

 a much deeper, retrograde current extending further from 

 the equator, whilst in the circumpolar regions we see the 

 normal rotation of the planet. Thus we get the shortest 

 rotation period in the equatorial currents, and the slowest 

 motion in the intermediate latitudes, where only the retro- 

 grading effect of the larger satellites is operating. This 

 superposition of layers may account for the occasional 

 passage of a mass of dark matter below the Red Spot, 

 for, by the hypothesis, the latter, a superficial disturb- 

 ance, is in the slower moving layer of the intermediate 

 latitude, whilst the dark matter, is a much deeper dis- 

 turbance reaching down to the more quickly moving norrnal 

 layer of the planet's atmosphere. Similarly, the proximity 

 of rings of ponderable matter to Saturn and the sun may 

 be held to account for the differential velocities observed 

 in different zones of the atmospheres of those bodies. 



Observ.itions of Planets. — In an account of the 

 observations made on the summit of Mont Blanc during 

 the period .August 31 to September 5, 1906, MM. Hansky 

 and Stef^nik give details of their observations of Venus, 

 Mercury, and Jupiter, made under nearly perfect atmo- 

 ".pheric" conditions. Difference In the markings seen near 

 the poles of \'enus and alterations in the contour of the 

 terminator suggested a rotation of the planet, a sugges- 

 tion which was apparentlv confirmed by the re-appearance 

 of the same aspects after a lapse of nearly twenty-four 

 hours. The two sets of observations made on September 

 -, and 4 gave the apparent rotation period as 23h. 20m. 

 \uid 23h. 25m. respectivelv. Three dark spots, one at the 

 middle of the terminator and two smaller ones near to 

 the eastern limb of the planet, were seen on Mercury on 

 September 5 at about sh. , . j ^ 



Numerous details of the observations of bands and spots 

 on Jupiter are also given (Comptes rendus, No. 23, p. 1252, 

 June 10). 



The Melbourne Observaiory.— According to the report 

 of the director, Mr. P. Baracchi, the astronomical work 

 of the Melbourne Observatorv for the period April i, 1905, 

 to November 30, 1906, was practically limited to meridian 

 observations and the work tor the Astrographic Catalogue. 

 For the latter, the total number of satisfactory plates 

 obtained was 191, of which ninety-three were triple- 

 exposure chart plates and thirty-two were for the duplicate 

 series of the catalogue; these bring the respective totals 

 up to 588 and 487. The measuring bureau is the joint 

 affair of the New South Wales and Victoria Governments, 

 and the total numbers of plates measured to date are :— 

 for Sydney, 551, containing 322,101 stars; for Melbourne. 

 836, conta'ining 21-8,714 stars. 



