312 



KNOWLEDGE. 



Al'GUST, 1911 



presented at a meeting of the Polytechnic Mathematical 

 Society, appeared in a letter to the then editors of 

 " Knowledge," which appeared in " Kno\vi.kdge " for July. 

 1908 {\'o\. V, page 157). A fuller statement will be found in 

 my " Matter. Spirit and the Cosmos " (Rider. 1910). Chapter 6. 

 together with some speculations bearing upon the same 

 subject. 



Thanking you in anticipation for affording this letter the 

 hospitality of vour columns. 



H. STANLEY KEDGROVE. 

 The Polytechnic. 



Regent Street. W. 



OBSERVATION OF URANUS AND MARS. 



To the Editors of " Knowledge." 



Sirs. — Uranus was observed on the early morning of July 

 1st, being located by aid of the circles on the equatorial of my 

 three-inch Mogey refractor; this is the first observation of 

 this planet I have made this year. It was pale blue or green 

 in colour, quite bright, and very attractive in its field of few 

 other and fainter stars. It presented quite a sensible disc, 

 power eighty-four diameters, and appeared as it usually does, 

 i.e., pale and diffused, like a star slightly out of focus. It is 

 of about magnification six, probably some brighter, and is 



easily visible in the one and one-eighth inches finder of my 

 three-inch telescope; as it is the only bright star in its 

 locality, it should be easily distinguishable even with an opera 

 glass. Probably Uranus would be visible to the naked eye in 

 clear air. especially as it is in an isolated position, to speak 

 relatively. 



Mars was also observed on the morning of July 1st. The 

 disc was rather large and very reddish, powers eighty-four 

 and one hundred and twenty-six. and was very beautiful ; 

 near a small star. The South polar cap was easily observable, 

 eightv-four and one hundred and twenty-six diameters, in my 

 three-inch instrument, and was attractive, being almost circular 

 and very white. At and around the South polar regions, 

 the disc was lighter than elsewhere and seemed to shade off 

 gradually into the cap. At or near the equatorial regions, an 

 apparently large continuous marking, running horizontally, 

 was seen, very similar to those visible in the fall of 1909, 

 through my two and a half inches refractor. This marking was 

 dark green in colour, and extended nearly the entire distance 

 across the disc, and at places was observed to be somewhat 

 irregular in outline. The planet also seemed to be slightly 

 gibbous on this date. FREDERICK C. LEONARD. 



LEON.\Rb Observ.\torv, 

 Madison P.\rk, 



Chicago, U.S.A. 



SOL.AR DI.SrURBA.XCES DURING JUNE, 191 1. 

 Bv FR.\NK C. DEXNI:TT. 



The Sun has been very free from spot disturbances during 

 the month of June. On the eleven days June 7. 8, 10-14, 16. 

 18, 19 and 24. there appeared to be a complete absence of 

 disturbance, and probably the 25th should be added, although 

 no observations have come to hand for that date. Only 

 faculic markings were seen on the disc upon the nine days 

 June 6, 9, 15, 17, 20-22,27 and 28. and some of these appeared 

 to be temporary in character. The longitude of the central 

 meridian at noon on June Ist. was 102 45'. 



No. 24 remained visible until June 5th. and so appears on 

 the present chart in its position on the 2nd. 



No. 24a. — .A group of four small pores. 15,000 miles in 

 length on the 2nd, which in the afternoon appeared to be 

 de\ eloping into an elliptical outbreak, but only the leader 

 continued visible on the 3rd. The area was marked by 

 facnlae, upon the 4th and 5th. which was joined to that 

 surrounding No. 24. 



No. 25. — A group of pores, three in number, only seen on 

 June 23rd. 



There was a greyish pore visible on the morning of June 

 28th in a pale faculic cloud near longitude 57°. South latitude 

 6°, marked by a cross on the chart, but not seen in the 

 evening. 



No. 26. — A spotlet. without penumbra, seen on the 29th and 

 30th only. 



Whether studied with the telescope or spectroscope, the 

 amount of disturbance is very small. The spots are generally 

 of an evanescent character, and are mostly found recurring in 

 the same districts of the solar surface, as may be noted by 

 comparing the monthly charts together. Of the thirty-one 

 spot disturbances recorded dm'ing the past six months seven 

 were northern. Of these one was in longitude 7°, four 

 between 103° and 146", one close to the equator, 170°, and 

 one at 226'. Of the twenty-four southern ones nine are 

 between longtitndes 35° and 86°, two between 120" and 130° 

 eleven between 165" and 203". and the remaining two between 

 243' and 253°. The intervening areas are thus left seemingly 

 without disturbance, in fact, from longitude 146° right round 

 to 103 — 317 — in the northern hemisphere, only three tiny 

 outbreaks occur. The longest vacant district in the southern 

 hemisphere — 140° — is between 254° and 35", three smaller 

 ones occurring between 86° and 120^ 130° and 165°. and 203° 

 to 243°. 



Our chart is constructed from the measures and drawings 

 of Messrs. J. McHarg, E. E. Peacock, and F. C. Dennett. 

 Absence from home has unfortunately prevented Mr. Buss 

 from sending in his work in time to be included this month. 



DAY OF JUNE, 191 1. 



10 JO 30 to so 60 70 aO 30 100 no 120 150 140 ISO 160 170 180 190 200 210 220 230 »0 250 260 270 2S0 290 300 310 J20 330 j-M JSO 360 



