Febri-ary. 1912. 



KN"0\VLi:i)CiE. 



59 



tion. therefore, seems assured. Among other e.xbibits already 

 amiounced. the Lick Observatory promises to send a set of 

 twenty sheets of the great photographic Lunar Atlas obtained 

 by means of thi- thirty-six inch refractor between USS9 and 

 liS'J5. together with a collection of transparencies on a large 

 scale specially intended for exhibition in various countries. 

 M. Fuisieux has intimated that the I'aris Observatory will be 

 pleased to exhibit a copy of the Lunar .\tlas which was the 

 culminating point in the work of the late M. Loewy. 

 and which represents one of the greatest triumphs of 

 modern .istrononiical photography. On behalf of the 

 Lunar Section of the Hritish Astronomical .Associa- 

 tion, Mr. t.oodacre will exhibit the superb collection of 



drawings recently shown at the Coronation Exhibition. 

 The Barcelona exhibition will be held in the University 

 buildings, under the honorary presidency of the Rector, 

 Baron de Bonet. The Executive Council of the Society 

 invite the co-operation of selenographers of all classes in 

 order to make this exhibition, the first of its kind, a great 

 success, and with this end in view, the Secretary would be 

 pleased to receive promises of assistance from any readers 

 who may be able to contribute exhibits, no matter how 

 modest, bearing on the subject. .\ll comnuniications should be 

 addressed to Senor Don Salvador Kaurich. Callo (Iran Via 

 Diagonal, 462, 2". B.ucclona. Spain. 



WM. I'ORTHOUSE. 



SOL.AK Dl.S ri RD.WCKS DL'RIXC, 1 )i:( 1:M IIKR, 191 1. 

 IJv FRANK C. DENNETT. 



.\ I'ARTHKR falling off in solar activity has to be recorded 

 during December. Continuous observation has been hindered 

 both by the low altitude of the Sun and the poor atmospheric 

 conditions. On thirteen days (4, 5, 6, 7, S. 9, IL 12, 16. 17, 

 25, 27 and 301 the disc appeared free from disturbance, and 

 faculae only seen on three (3, 14, and 19). .At noon on 

 December 1st the Central Meridian was 205° 21'. 



from longitude 258 to 269'. Again on the 24th there was a 

 bright patch south of Xo. 41, in latitude estimated as being 

 between 30' and 40 '. 



The only observers able to make efiective telescopic 

 observations were Messrs. McHarg, Buss, and Dennett. 



Our second diagram shows the positions of the whole forty- 

 seven spot disturbances seen during the year 1911, six of 



DAY OF l)i:CKM15ER, 191 i. 



S m 20' 30' «' 50 



95 W 10' 120' 150' W !»' I6(f W 



190' 200' 210' 220' 23flr 2rf 250' 260' 27J' 280' 29Cf XO' 310' 320' 330" 5*0' 350' 3«0' 



No. 41. — Apparently the only spot disturbance during the 

 month. On the 20th there was a small spot found in the 

 southern spot-zone, the leader of a trail of pores only 22,000 

 miles in length. When next seen, on the 23rd and 24th, it 

 was as a solitary penumbraless spotlet with a ragged border, 

 and which was quite gone by the following day. 



The only other disturbances seen were faculic. On the 3rd 

 such a disturbance was seen within the south-western limb. 

 which must have been situated a little south-east of that 

 shown on the monthly diagram on longitude 260°. On the 

 14th a small knot near the western limb, in longitude 102° 

 marked the place where No. 39 had disappeared. On the 

 19th an extensive district streaked with faculae, around the 

 site of No. 40. was visible within the eastern limb, reaching 



which were rather secondary or attendant outbreaks. Thirty- 

 two were in southern latitudes, and fifteen in northern. The 

 distribution of the disturbances is a striking feature. In the 

 southern zone, between J5° and 1.30° there are fifteen out- 

 breaks. Between 1 66° and 203 ' twelve more, with five between 

 241- and 263°. whilst situated by itself is No. 41, between 287° 

 and 290 . Thus it will be seen that from 1.50° to 166', 203° 

 to 24I%263° to 287% and 290' to35° the surface has apparently 

 been quite free from spots. In the northern zone three small 

 disturbances have occurred between 6° and 38°, seven between 

 103' and 170°, and five between 213° and 258°. The regions 

 between 3S° and 103'. 170= and 213°, also 258° and 6° in the 

 northern hemisphere, have also thus been free from outbreak 

 as well. 



DISTRIBLTIOX OF SPOT-DISTURBANCES, 191 1. 



« irf 20" ilS W 50' 60' Ttf bJ Stf KKf IKf I2tf Wf Ktf ISIf teJ \JS 180" IStf M 20' ZlfS li<! li,t 250' 9>lS ITS ZM J90' JOO" SKT 320' 3J(f Mf 550' 360" 



