346 



KNOWLEDGE. 



September, 1911. 



in or near the Milk\ W'av. a fact which led Sir \\'. 

 Herschel, quite earlv in his career, to infer the 

 existence of a ckistering power, akin to gravitation, 

 which is gradually breaking up the Galaxy, and 

 has already given that "great arch of light, the 

 aspect of a series of clusters rather than that of a 

 uniform band of milk\- light." Professor See. in his 

 great work " Researches on the Evolution of Stellar 

 Sx'stems "■ (\'ol. ID. has however, pointed out the 

 important effect of the uni\'ersally diffused cosmical 

 dust, which acts everywhere as a resisting medium, 

 so that " the Milk^ \\'a\' may have been alw ays more 

 or less aggregated into clusters, which have simply 

 grown denser or become more dispersed with the 

 flight of ages." If these clusters arose from the 

 condensation of nebulous material, and this diffused 



" cosmical dust " acts everywhere, it follows 

 ncii'ssarih- that all clusters will, in course of time, 

 become more dense and more nearly globular, unless 

 the aggregations thus going on are dispersed by the 

 action of external forces due to other clusters. 

 Space will not permit our pursuing this interesting 

 subject further, but it must be fairly exndent that the 

 study of the nature and conditions of formation, 

 growtli and deca\- of these objects is one of the 

 grandest with which the human mind can be 

 emplo\'ed. \\"e owe much to the patient labours of 

 ■■ self den\ing men of science " but more lies for the 

 future to unravel, and as there appears to be neither 

 end nor beginning to the Universe of God, so also 

 must we believe that its complete comprehension 

 w ill for ever transcend the finite mind of man. 



SOLAR DISTURBAXXES DURING JULY, iqii. 



By FRANK C. DENNETT. 



There has been a very slight increase m the amount of solar 

 disturbance during July, but on four days (6th, 11th, 25th and 

 26th) no trace of activity was visible, bright nor dark, and on 

 sixteen days (5th, 7th— 10th, 17th— 24th, 27th. 2Sth and Jlst) 

 only taeniae could be seen. The longitude of the central 

 meridian at noon on July 1st was 65 41'. 



No. 27. — When first seen on the afternoon of J ul\' 1st it was 

 a single pore, but next day there were three forming a long 

 triangle 25.000 miles in length. It was not seen on the 3rd. 

 but a pore showed on the 4th. 



No. 28. — A solitary spotlet only seen on the 2nd and 3rd. 

 No. 28a. — A group of four pores 23,000 miles in length, 

 forming two pairs, only seen on the 4th. 



No. 29. — Two spotlets, the western largest and accompanied 

 by two pores, were visilj e on the 12th. During the next day 

 considerable Iteration took place in the group, by the afternoon 

 the rear spot had enlarged considerably and thrown forward a 

 sort of tail which broke into a line of small umbrae, having in 

 front of them a small triangle of pores. On the 14th the rear 

 spot was about 5,000 miles in diameter, with a curve of pores on 

 the northern side and line of pores in front, having a total length 

 of 52,000 miles. On the 15th its length was unchanged but 

 its members were shrinking, and on the 16th onlv the hinder- 



most spot was seen cut in halves by a bridge, with a tiny 

 pore to the south. Not seen after, except its faculic remains 

 near the western limb on the 19th, 20th and 21st. 



No. 30. — A group of three pores, one very tiny, 18.000 miles in 

 length, on the afternoon of the 29th, but on the 30th only two 

 minute pores seen close together, and not seen after. 



No. 31. — A pore visible on the northern border of a bright 

 faculic disturbance on the 30th. but not observed after. 



On the afternoon of July 8th. a very pretty prominence 

 eruption was witnessed, though on a very small scale. In 

 adjusting the position circle of the spectroscope, a bright little 

 bead was noticed only S' west of the north pole. Within a 

 very few minutes it threw up a fine needle of light which 

 slightly expanded, then bent over polewards and began 

 drifting off as clouds. The positions of the other prominences 

 around the limb were measured, then on returning to the same 

 point only a little bead of light remained. The position of the 

 bead was measured at 5.45 p.m.. and the observation was 

 completed at 6.10, so that the eruption could only have 

 occupied a few minutes. 



Our chart is constructed from the combined observations of 

 Messrs. John McHarg, E. E. Peacock, and V. C. Deiniett. 



DAY OF JULY, 19 ii. 



^ A SI 3, pO g p9 I, f8 "p ?6 25 if. 2^ Sf 2,\ 2,0 19 16 1^ Ij5 15 l-t Ip I? rl 10 9 B 7 ^ 



t7 



30 



E" 



W 



ISJi. 



.0 so <.l) 50 60 70 80 90 100 110 120 150 l«) ISO 160 170 180 M 2O0 ,'10 220 ZX 2+0 250 !6C 270 280 290 500 JIO 320 3J0 3*0 350 «0 



