October 1, 1900.] 



KNOWLEDGE. 



227 



usual or extraordinai-y in. the position of these dark rays. 

 I at first considered them to be merely spaces between 

 the ordinary polar rays, but I now think that they are 

 slightly darker than the sky. The development has 

 been carried faa' enough for the light of tho sky to 

 impress itself on tho plates ; but for this fact the mark- 

 ings woidd appear simply as interspaces, but on these 

 plates I think I can just see the ends of the rays, ter- 

 minating at about two-thirds of a lunar diameter from 

 the limb. They cannot be traced to the limb, as they 

 are lost among the mass of bright rays, and they are 

 lost in long exposure negatives. These markings are 

 feir more difficult to see than those in 1896, but if they 

 are, as I think, darker than the sky, wc seem to have 

 taken a considerable step towards proving their objective 

 exist€nce. 



We now come to the negatives taken by Mr. Maunder 

 at Algiers during the eclipse of May last. On two 

 negatives taken on Sandell plates with very long ex- 

 posures, and on a series of negatives exposed by Miss 

 Maunder with i sec. exposures in a stationary camera, arc 

 certain dark streaks of much the came chaxacter as those 

 of 1898, but unlike these, they are most easily seen; 

 in fact on some of the plates they strike the eye at once. 

 One of them forms a shai-p boundary to the northern edge 

 of the western equatorial streamer, and one bounds in the 

 same manner its southern edge, while another radiates 

 from the limb near the centre of the great southern 

 rift; there are several others that may be suspected. 

 The only point in doubt is whether they are unusually 

 definite spaces or rifts between bright rays, only seeming 

 dark by contrast, or whether they are actually darker 

 than the sky. If they are darker than the sky we seem 

 forced to admit that they are real, however impossible 

 it may be to offer any physical explanation for their 

 existence. We cannot isolate these fine, narrow dark 

 streaks, so as to avoid the effect of contrast. They are 

 visible on all the six plates of the short exposure series, 

 and the dark markings forming the north and south 

 boundaries of the western portion of the corona are 

 very strikingly shown on the long exposure negatives. 

 These dark rays bounding the coronal extension are 

 extremely remarkable, and it seems impossible to regai-d 

 them as effects of contrast. For while on the one side 

 they are each bounded by the edge of the coronal 

 streamer, there is apparently no ray bounding them on 

 the other side, and they appear to extend beyond the 

 coronal streamer itself. If this is so, they are obviously 

 darker than the sky, or the faint nearly unifonn light 

 which forms their background.* The dark marking 

 bounding the southern edge of the western coronal ex- 

 tension is the most conspicuous. 



The narrow, slightly cvu'ved dark ray near the centre 

 of the southern rift, is well shown on the short exposure 

 negatives. It has a distinct temiination at a distance 

 of about half a lunar diameter from the limb — a ter- 

 mination in fact more definite than those of the bright 

 coronal rays. It seems decidedly darker than its back- 

 ground of sky or faint coronal light. If this marking 

 is merely a rift, or interspace, it must be a rift dosed 

 at its outer extremity, which apjjears a most improbable 

 supposition. 



I am quite unable to offer any explanation of such 



• It is probable, as Mr. Maunder lias pointed out (Knowiedse, 

 August, ISKX)), that there is a considerable amount of diffused coronul 

 light beyond the limit? of the detailed corona. This appears to be 

 borne out by Prof. Turner's photometric measures of the negatives of 

 the eclipse of 1893. 



features as these, but I think we cannot resist tho 

 evidence for their reality. As Mr. Maunder has said, 

 they must be caused " by the interposition of actual 

 dark absorbing matter between ourselves and the general 

 diffused coronal glow " ; so that the corona appears to 

 be " not wholly an emission, but partly an absorption 

 effect.' The nearest analogy to them arc the thick rays 

 in the prominences to which Trouvclot drew attention, 

 and which I believe Mr. Evershed has confirmed. 



I have just examined some excellent negatives taken 

 by Miss Bacon at Wadcsborough, U.S.A., which clearly 

 show the dark markings visible on Mr. Maunders 

 plates. 



[The eight photographs of the 1900 eclipse to which 

 Mr. Wesley refers in the above paper were as follows: — 

 Two taken with a Dallmeycr stigmatic lens, IJ inch 

 aperture and 9 inches focal length, on Sandell triple 

 coated plates, and six with a 4 inch lens, presented to 

 the British Astronomical Association by Mr. G. E. 

 Niblctt, of the Royal Obscrva,tory, Greenwich. Focal 

 length, 34 inches. Plates — Imperial, Extra rapid 

 Ordinary, and Fine grain Ordinary. — E. Walter 

 Maunder.] 



-♦ 



Hctttrs. 



[The Editors do not hold themselves responsible for the opinions 

 or statements of correspondents.] 



• 



ASTROLOGY. 



TO THE EDITORS UF KNOWLEDGE. 



Sirs, — Referring to your Editorial note to my letter 

 in the September number of Knowledge, permit me 

 to express my opinion that there is something to examine 

 in astrology, and that though it is possible that 

 astrologers were and ai-e self-deceived, they are most 

 decidedly not impostors. They do not go on blindly 

 accepting the old teachings, but do their best to rectify 

 and allow for any irregulai'ities they may discover. 

 " Astrologei's can neither tell when or how the special 

 ' influences ' supposed to reside in each individual 

 ' planet ' or ' house ' were determined, nor give the 

 observations upon which primitive astrology was based " 

 because thousands of years have elapsed since these 

 data were established, and we have, like astronomers, 

 no traditions or records to guide us, but it is only fair 

 to assume that the early star-gazers were led to compare 

 the planetary motions with events until the present 

 system was formulated, possibly in Sumers-Akkadia, 

 Hindustan, or Egypt, who can say ? 



You say in your remarks '' The ancients i-ecognised but 

 seven planets, whereas there are — according to modern 

 astrologers — nine. That is to say, in the opinion of the 

 ancients Uranus and Neptune had no influence, for they 

 never detected anything wrong in their calculations, as 

 they should have done if these planets were really 

 potent." It cannot be denied that modern astrologers do 

 ascribe influences to Uranus and Neptune. They, however, 

 agree that the influence of Neptune is reduced to almost 

 nil by his great distance, and that Uranus only affects 

 when in positions astrologically powerful for a similar 

 reason. It is true, however, that in some instances, 

 when nativities have happened at these periods at a time 

 when the existence of this planet was unknown, the 

 astrologer has foimd his predictions to a certain extent 

 falsified in subsequent events, but these cases arc 

 exceptional. On the whole the ancients could prog- 



