October 14, 1915] 



NATURE 



179 



derivatives ; but as the gas gives an absorption-band at 

 wave-length 2961, it is suggested that the absorbent 

 compound is a hydrated form of sulphur dioxide 

 formed according to the scheme — 



(x-i)H,0 + H,SO,^SO„A.-H,0. 



The use of chains for power driving has increased 

 greatly, and we note with interest from the Engineer 

 for October 8 an account of a chain drive transmitting 

 about 5000 horse-power in a hydro-electric plant on 

 the Snake River in the State of Oregon. The chains 

 connect the waterwheel shafts to the generator shaft, 

 and the arrangement was designed to meet conditions 

 imposed by financial considerations. These conditions 

 necessitated the adaptation of generators designed for 

 direct connection to waterwheels running at 225 revs, 

 per minute under 50-ft. head, to the same wheels 

 running at 160 revs, per minute under 20-ft. head. 

 The generator is of 3600 kilowatts, three-phase, 

 60 cycles, and had to be operated at the intended 

 speed. The problem was solved by chapging the 

 position of two waterwheel units, providing additional 

 shafting, and driving the generator shaft from the 

 two waterwheel shafts by driving chains and sprocket 

 wheels. Each set of driving chains consists of four 

 Morse silent chains, 22 in. wide, and transmits 2500 

 horse-power. This is believed to be the most powerful 

 chain drive plant in the world, the nearest to it being 

 that at Indianapolis, which drives a 1200 horse-power 

 generator. 



OUR ASTRONOMICAL COLUMN. 



Comet igi-^d (Mellish). — A card from the Copen- 

 hagen Observatory informs us that the following 

 elements and ephemeris have been calculated by 

 Messrs. Braae and Fischer-Petersen for Mellish's 

 comet from observations at the Yerkes Observatory 

 on September 18 and the Lick Observatory on Sep- 

 tember 19 and 20 :— 



T = i9i5 Oct. ir933 M.T. Berlin. 



^=72' 5o'-i7 11915-0 

 t = 49° 4 1 '-62) 

 log g =972054 



Oct. 



A Large Fireball.— Mr. W. F. Denning writes :— 

 "On the night of October 5 at loh. s6m. Mrs. Fiam- 

 metta Wilson saw a large fireball from Portscatho, 

 near Falmouth. It appeared in the N. by E. sky, its ob- 

 served path being from 140° + 68° to 126° -h 57°. A 

 remarkable feature about the object was that it left a 

 streak which remained visible for 17^ minutes, and 

 underwent some curious transformations during the 

 time it continued luminous. .At first a straight band 

 of glowing light, it gradually resolved itself into a 

 large oval, which drifted slowly eastwards. 



"The meteor must have been one of the most brilliant 

 which has appeared for some time, and it is desirable 

 NO. 2398, VOL. 96] 



to obtain further observations, both of the flight of the i 

 object and of the successive positions of the streak it ; 

 left." i 



Mr. Arthur Mee sends us the following note upon I 

 the object : — i 



"A remarkable meteor was seen in south-west i 

 Wales on the evening of October 5. An observer at .' 

 Mumbles says it appeared at seven minutes to eleven, j 

 and that the ' tail ' retained its form for a minute 1 

 and a half, and then gradually took the appearance of j 

 a hook, broadening as it did so, and finally fading i 

 away some seven minutes later. The meteor itself * 

 was so brilliant that it alarmed a dog and made it , 

 run indoors. An observer at Milford Haven says the 

 appearance after the explosion of the meteor was that 

 of a luminous cloud, * a gigantic smoke-ring with I 

 wings.' It was first noticed in the zenith, and then | 

 gradually drifted in a north-easterly direction, becom- 

 ing more diffuse, and finally disappearing soon after j 

 II o'clock. It was a bright, starry night, and the '• 

 meteoric cloud was evidently self-luminous; the stars - 

 were seen quite clearly through it." 



Recent Observations ok Variables. — One of four ] 

 variable stars discovered by Dr. Silbernagel in 1907, i 

 since designated SS Aurigae, belongs to the small i 

 class of long-period irregular variables of which U ' 

 Geminorum is the best-known example. Almost from ] 

 discovery it has received attention at Utrecht, where \ 

 a large number of visual observations have been made ; 

 by Prof. A. A. Nijland and Mr. van der Bilt (Astr. I 

 Nach., 4814). Although most of the time it remains ', 

 beyond visibility in the lo-in., twenty-five of its rather \ 

 sudden accessions of lustre were followed during ; 

 1912-13. Of these, fourteen were "long" and eleven i 

 "short" maxima; correspondingly it was recorded \ 

 brighter than i4-om. for periods on the average of 

 146 and 8-2 days, attaining in the one case to io-7m., ' 

 in the other only reaching iiom. The mean curve ■ 

 for the "long" type of maximum almost precisely ] 

 parallels that of U Geminorum, the latter being just ! 

 one magnitude brighter. At Harvard the minimum \ 

 brightness of SS Aurigae has been measured as i5-9m., 

 equivalent to i4-7m. in Prof. Nijland's svstem. \ 



Mr. Torvald Kohl (Astr. Nach., 4813) obtained ] 

 further observations of 25, 1913, Ursae Majoris during j? 

 January-March of this year, from which the period ] 

 of twenty-eight days gains additional weight. ! 



A new variable star, 2, 1915, Cephei, has been found j 

 by M. Kostinsky, using the stereo-comparator {Astr. ■! 

 Nach., 4809). The photographic magnitude increased \ 

 by three units between November 29, 191 1, and ' 

 November 6, 1913, when it was loom. M. Blazko , 

 has made confirmatory observations. 



The Victorian Observatory. — The existence of ■ 

 this institution — better known as the Melbourne Ob- ; 

 servatory— is now definitely threatened. From Aus- \ 

 tralian papers we learn that the State Astronomer, j 

 Mr. P. Baracchi, tendered his resignation last August ; 

 after some thirty-nine years of Government service, j 

 the last fifteen years as successor to Mr Ellerj-. ' 

 .\ccording to the Age, no successor is to be ; 

 appointed, the State Government having decided ] 

 to drop the work, thereby saving upwards of 4000Z. | 

 annually. We trust some scheme of Commonwealth \ 

 control will be evolved before it is too late. | 



The Proper Motion of A.G. Wa. 5002. — In .4str. ] 

 Nach., No. 4814, Mr. R. J. Pocock, Nizamiah Ob- \ 

 servatory, Hyderabad, states that this star. No. 267 j 

 in Mr. van Maanen's recent list of proper-motion ] 

 stars, has been photographed on two astrographic ! 

 plates, neither of which shows any trace of proper * 

 motion. 



