414 



NATURE 



[July 25, 191 



also sets of botanical serials. Among the latter we 

 notice Curtis's Botanical Magazine from 1787 to 1906; 

 Edwards's Botanical Register, a complete set; 

 Maund's 'Botanic Garden," large-paper edition; the 

 Transactions of the Linnean Society of London, com- 

 plete to 1916; the Orchid Album; the Orchid 

 Review; the Phytologist, by Luxford, Newman, 

 and Irvine, all published. Messrs. Wheldon also have 

 for disposal a large-paper copy of Loddige's 'Botanical 

 Cabinet," complete in 20 vols. 



OUR ASTRONOMICAL COLUMN. 



Periodic Comets. — Wolf's comet was detected by 

 Prof. Barnard at Yerkes Observatory on July 12, 

 three days later than M. Jonckheere's first observa- 

 tion. M. Kamensky's predicted date of perihelion, 

 1918 December 133899, appears to be too early by 

 0053 id., which is not a large error, and the ephemeris 

 given in Nature for July 11 will suffice for finding 

 the comet. 



Borrelly's periodic comet will pass perihelion a 

 month ea'rlier than Wolf's, and the conditions will be 

 favourable for observation. Mr. L. v. Tolnay gives 

 the following ephemeris in Ast. Nach., No. 4948; it 

 is for Greenwich midnight : — 



S. Decl. 



Logi 



Log A 



R.A. 



h. m. s. 



July 29 3 19 o 17 I 02653 0-2107 



Aug. 2 3 28 5 16 41 0-2591 0-1972 



6 3 37 10 16 21 02529 01835 



10 3 46 15 16 I 02467 0-1696 



14 3 55 i^ 35 41 02405 01554 

 18 4 4 iq 15 20 0-2343 . 0-1411 

 22 4 13 17 14 59 0-2282 0-1265 



26 4 22 12 14 37 0-2222 0-IIl6 

 30 4 31 4 14 13 0-2162 00964 



The perihelion passage is about November 16-65, 

 log = 0-5598, e = 0-6153, log 5 = 0-1450. 



The Period of Sirius. — ^The companion to Sirius 

 has lately been more easily observable than during the 

 previous forty years, and has completed rather more 

 than a revolution since its discover}- in 1862. Mr. R. 

 Jonckheere has obtained measures with the 28-in. refrac- 

 tor at Greenwich In the course of the last four winters, 

 and has taken the opportunity of making a revised 

 estimate of the period (Monthly Notices, R.^^.S., 

 vol. Ixxvlil., p. 480). The mean result Is 5002 years, 

 which is 1-78 years shorter than that given by Burn- 

 ham. The shortest period ever given Vk^as that of 48-84 

 years, arrived at by Zwiers, and the longest that of 

 58-47 years given by Gore. Mr. Jonckheere recalls that 

 nearly eleven years before the visual discovery Peters 

 made an Investigation of the orbit from transit ob- 

 servations, and although the maximum displacement 

 was only 0152s., he obtained the closely accurate period 

 of 5001 years. Adopting the parallax 0-38" and a 

 semi-major axis of 7-5", the corrected mass of the 

 system is 3-07 times the mass of the sun. 



Two Spectroscopic Binaries of Long Period. — 

 The spectroscopic binary 32 0^ Cygni has been under 

 observation at the Dominion Observatory, Ottawa, by 

 Mr. J. B. Cannon since 1914, and a preliminary orbit 

 has now been determined (Astrophys. Journ., 

 vol. xlvil., p. 193). The period of this star Is more 

 than three years, and the eccentricity of the orbit 

 0182, but there are irregularities which suggest the 

 presence of a third body The velocity-curve may be 

 explained by considering the system as consisting of 

 a luminous star revolving about another body in a 

 circular orbit in 390 days, and the pair revolving in 

 NO. 2543, VOL. lOl] 



an elliptic orbit about a third body in 1170 days. Tl^ 

 star is of spectral type G5 and magnitude 5-15. 



A spectroscopic binary of still longer period has 

 been under investigation at the Cape Observatory by 

 Dr. J. Lunt since 1903. The star In question is 

 oPhoenicis, and the period has been found to be 

 10-62 years, or 3880 days. The eccentricity of the 

 orbit is 032, and the system is receding with a velocity 

 of 7576 km. As regards length of oerlod, the star 

 Is second only to Polaris, which has a period of 

 11-9 years. The star is of magnitude 244 and of 

 t}pe K. 



Stonyhurst Coliece Observatory. — The annual 

 report of this observatory for 1917 includes a valu- 

 able record of the state of the Sun's surface on 

 210 days of observation. In units of one five- 

 thousandth of the visible surface the mean disc-area 

 of the spots was 12-1, which Is about three times 

 greater than that of the previous year, ^nd twice as 

 great as at the previous maximum. The increased 

 activity commenced early in February and reached its 

 greatest intensity in August, the greatest area on any 

 one day being 50 units on August 11. The February 

 and August groups were of exceptional size, and second 

 to none that have appeared during the last thirty- 

 eight years. As regards the ranges of magnetic 

 declination and horizontal force, the year was rela- 

 tively quiet and out of accord with the solar activity. 

 A comparison of the Stonyhurst drawings with spectro- 

 heliograms taken at the Yerkes Observatory has shown 

 an almost perfect agreement between the faculse and 

 the calcium flocculi, but no similarity with the 

 hvdrogen flocculi. The report also Includes particulars 

 of meteorolegical and magnetical observations. 



THE FUTURE OF THE ELECTRICAL 

 TRADES. 

 nPHE Departmental Committee appointed by the 

 ■•■ Board of Trade to consider the position of the 

 electrical trades after the war, with special reference 

 to International competition, has now issued a Report 

 (Cd. 9072, price 2d.). Like other similar Committees, 

 this urges that "remedial and unifying legislation 

 governing the supply and distribution of electrical 

 energy should be Introduced forthwith." A historical 

 rdsumd of electrical enterprise in this country is given, 

 and it is pointed out that, like the automobile In- 

 dustry, It has been hampered all through by the lack 

 of a scientific outlook on the part of the officials of 

 our Government Departments. Acting according to 

 their lights, they encouraged competing companies 

 using different types of plant and different systems to 

 set up in the same area, the reason given being that 

 the healthy competition would cheapen the supply to 

 the consumer. The mischievous effect of this policy 

 is well Illustrated by the circular issued by the Board 

 of Trade in 19 16 calling on the supply companies to 

 Imk up with one another in the national interests so 

 as to reduce the consumption of coal and economise 

 labour. That is, after making it practically impossible 

 for the companies to link up, the Board calls on them 

 to do so. 



Looking to the future, the Committee points out 

 that as the supply of electrical energy is a "key 

 industry," it is imperative that questions concerning 

 it should be prevented from becoming party questions. 

 They should be considered solely on their merits from 

 the point of view of national requirements. We quite 

 agree, but we are afraid that this Is a counsel of 

 perfection. Few questions are of greater urgency 

 than that of standardising some system for electrifying 



