SOLAR DISTURBANCES DURING FEBRUARY, 1913. 



BY FRANK C. DENNETT. 



February has yielded a much better proportion of observing 

 days than did the previous month. On only two — 3rd and 

 12th — was the sun quite missed, but of the remaining days 

 the disc appeared quite free from disturbance on no less than 

 fifteen, as none was seen until the 18th. The central meridan 

 at noon on February 1st, was 318° 0'. 



No. 4. — On the 18th a bright faculic cloud was noted round 

 the north-eastern limb, which on the evening of the 19th was 

 found to contain pores. On the 20th there were three spotlets 

 and some minute pores, but next day the leader was some 

 9,000 miles in diameter, and the group about 45,000 miles in 

 length. On the 22nd and 23rd a trail of three or four pores 

 stretched back from the southern side of the leader, and a 

 somewhat lesser trail reached forward from the back spotlet, 

 the group now extending over 82,000 miles. From the 24th 



to the 26th, only the leader was visible with a small pore 

 closely south-east, the latter being gone on the 27th. On the 

 28th only the faculae remained visible in place of the group. 

 The high northern latitude of this disturbance quite marks it 

 as belonging to the new cycle. 



Although only one disturbance has been recorded during 

 the month, and that showing but little activity from a spectro- 

 scopic point of view, except upon the 21st and 22nd, when 

 the C. line showed much deflection, and at one time an 

 eruptive flocculus, it is probable that during the present 

 year there will be a gradual but marked increase of 

 disturbance. 



The observers have been Messrs. John McHarg, C. J. 

 Simpson, D. Booth, W. H. Izzard, C. Frooms, E. F. Peacock, 

 and the writer. 



DAY OF FEBRUARY. 



I ZO X 40 50 60 70 80 SO 100 110 120 130 140 150 160 170 180 190 ?00 210 220 230 240 250 260 270 280 290 300 310 320 330 340 350 360 



NOTES. 



ASTRONOMY. 



By A. C. D. Crommelin, B.A., D.Sc, F.K.A.S. 



STELLAR PARALLAX. — An important programme in 

 this field has been carried out at the Observatory of Yale 

 University by Messrs. F. L. Chase and M. F. Smith. An 

 interesting summary of the results is given in Popular 

 Astronomy for Februarv, which we reproduce below in 

 Table 30 :— 



on account of sensible proper motion. The following large 

 parallaxes were found : — 



Par. 



e Eridani "-31 



S Eridani ... ... ... -18 



W.B. XVI 906 -21 



The last is a faint star of magnitude 8-8, the proper motion 

 being l"-29. e Eridani appears to be one of the Sun's twelve 

 nearest neighbours. 



Table 30. 



As might be expected, the parallax increases with the proper 

 motion. The dependence on brightness is less marked, but it is 

 to be remembered that while the list is fairly exhaustive for 

 the brighter stars, it only contains selected faint ones, chosen 



SUN SPOTS. — Mr. Maunder contributes an interesting 

 article on Sunspots to the January number of Scientia. He 

 first points out the abruptness of the transition from spot- 

 activity to quiescence, which is frequently accomplished in a 



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