SOLAR DISTURBANCES DURING MARCH, 1913. 



BY FRANK C. DENNETT. 



Only one day has been quite missed during the month, 

 namely, March 4th. The spot disturbances have been both 

 few and insignificant in appearance, yet one at least was of 

 importance. The disc appeared to be quite free from disturb- 

 ance on twelve days (3rd, 7th, 9th, 10th, 15th to 17th, 22nd, 

 23rd, 26th, 27th, and 31st). The central meridian at noon on 

 March 1st was 309° 17'. 



On March 8th, at 1.30 p.m., there was an evanescent group 

 of minute pores in high southern latitude, but clouds prevented 

 the exact determination of their position. Observations 

 earlier in the day failed to reveal them. 



No. 5. — A small pore close to a faculic patch seen on the 

 13th and 14th only. It was specially noticeable owing to its 

 high latitude, 34° South. 



No. 6. — A group of pores only seen on the 28th, very near 

 to the equator. 



The photosphere appeared to be in an active state on the 

 27th, dull spotlets appearing and disappearing in the north- 

 western quadrant. 



Faculic patches were visible in the south polar regions on 

 the 5th, 6th and 8th, also on the first two dates close to the 

 equator, near longitude 180°. On the 1st and 2nd the faculic 

 remains of No. 4 were visible near the north-western limb, 

 and from the 18th to the 21st were advancing from the north- 

 eastern limb, re-appearing on the 29th as they approached 

 the north-western limb. On the 29th and 30th another 

 patch around longitude 225° was visible near the north- 

 eastern limb. 



Our chart is constructed from the observations of Messrs. 

 John McHarg, E. E. Peacock, W. H. Izzard, A. A. Buss, and 

 the writer. 



DAY OF MARCH. 



3 



3t, ta ;t a -ip if if ij ib is n. is it ». y. ? 



7 6 1 i 



£££ 



l. 25 I, 28 V. X IS. 



15" 



E 



W 



N 



«*K 



'0 3 JO to * 60 D » » 



no m in m 



no m iso no iao 2io m no m so no vo 



m m no so no no m 



CORRESPONDENCE. 



PHYLLOTAXJS AND THE DISCAL FLORETS OF 

 COMPOSITE FLOWERS. 



To the Editors of " Knowledge." 



Sirs, — A few months ago I published a paper in "Know- 

 ledge" on the ray and discal florets of Seuecio Jacobaea. 

 The following note is a supplement to it. The plant, of which a 

 specimen is appended, so that you may have it identified, is 

 fairly common about Cordoba. In appearance, it is something 

 between our blue cornflower and a rampion, with the colouring 

 of the latter. It is well-suited for the purpose, the sterile ray- 

 and fertile discal-florets being neither of them very numerous, 

 but there was not enough of the plants to repeat, on anything 

 the least like the same scale, the elaborate observations on the 

 small wild calendula, nor for that matter was there any reason 

 for attempting it. At the same time the present observations 

 seem to put beyond any reasonable doubt the fact that the 

 coincidence shewn in the number of the florets with numbers 

 indicating a system of concentric rings is far more than 

 chance would give. The reasoning is simple enough, and I 

 do not think there is any serious flaw in it. The number 

 of circular ring systems was found for the digit series from 

 the lowest discal number to the highest discal number + the 

 ray florets, and the percentage of coincidences was found to 

 be nearly three times what chance would give. Taking, how- 



ever, what may be considered the normal types of flower head 

 with 17, 18 and 19 rays, the percentage was much higher. In 

 fact, for the 18-rayed type it was 90-9 instead of 20%. For 

 the sake of brevity QT), (V), (jf), and so on, are put for " a 

 system of concentric rings beginning with 3, 4, 5, and so on." 

 When a number has one dot over it, that means that it 

 belongs to a ring system, either with or without the ray 

 florets being counted in; when two, that it belongs to both. 



Table 36. 



Giving all the ring systems in the tract of numbers to 

 be dealt with, viz., from 28. ..to 100 or 72. 



\i 



