630 



NATURE 



[October 27, 1898 



OUR ASTRONOMICAL COLUMN. 

 Astronomical Occurrences in November :— 

 November i. 5h. 17m. to 6h. cm. Occultation of 103 Tauri 

 (mag. 5 "5) by the moon. 

 5. 4h. Mars 3° 41' N. of the moon. 

 12. Mars rises at gh. and visible afterwards through- 

 out the night in Cancer. Diameter of the 

 planet 9" •6. 

 15. Mars. Illuminated portion of disc = 0900. 

 15. Jupiter becomes visible as a morning star. Polar 

 diameter 28" 8. 



15. Meteoric shower from Leo in the early morning 



hours. (Radiant 149° + 23°.) 



16. 7h. Vesta 10' N. of the moon. 



■ 17. loh. urn. Minimum of Algol (;8 Persei). 

 20. 7h. Minimum of Algol ()3 Persei). 

 22. 7h. 9m. to 8h. 13m. Occultation of 19 Piscium 



(mag. 5 '2) by the moon. 

 23-24. Meteoric shower from Biela's comet. (Radiant 



25° +43°-) 

 25. I2h. Uranus in conjunction with the sun. 



28. I4h. 7m. to I5h. 6m. Occultation of 103 Tauri 



(mag. 5 '5) by the moon. 



29. iih. 19m. to iih. 49m. Occultation of the star 



DM + 24°, 1033 (mag. 6*o) by the moon. 



Comet Brooks. — A telegram from Kiel, dated October 21, 

 informs us that at 7h. Geneva time, on October 20, Brooks 

 found a comet in position R.A. I4h. 32m. 8s. and Decl. + 60° 26'. 

 It was moving in a south-easterly direction, and was described 

 as "bright." A later telegram, dated October 22, gives the 

 position of the comet from an observation made at Pola on 

 October 21, at i6h. 48"5m. Pola mean time ; this was 

 R.A. I5h. 4m. I2S. and Decl. + 57° 50'. 



The comet was thus situated in the constellation of Draco, and 

 moving to the south of the star fi Draconis. 



The Large Sun-spot.— In this column for September 8 

 we drew attention to the large spot that had a few days pre- 

 viously made its appearance on the eastern limb of the sun, and 

 remarked that " the spot will be well worth watching during 

 the remaining period of its visibility, especially as many years 

 may perhaps elapse before observers are favoured with another 

 spot of similar size." 



At the present time there is another great spot, larger, per- 

 haps, than the one referred to above, which is now beautifully 

 visible near the centre of the solar disc. This very compact 

 group, which is not situated very far from the solar equator, is 

 composed of two large umbrae surrounded by rather irregular 

 shaped penumbrae, with several small spots scattered around 

 them. Another smaller spot is also following the large one. 



It will be well for observers to look out for an aurora and 

 magnetic storm when the spot passes the central meridian, as 

 was the case when the spot, previously referred to, was in the 

 same position on September 9 last. 



The Harvard Astrophvsical Conference. — It was on 

 the occasion of the dedication of the Yerkes Observatory that 

 the Americans held their first astrophysical conference. So 

 great was the success of this, their first trial, that it was expected 

 that more would be held in after years. For this we had not 

 long to wait, and we have now before us a full account of the 

 conference recently held at Harvard, the oldest observatory 

 devoted to astrophysical research, contributed to Scietice 

 (October 7) from the pen of Prof. M. B. Snyder. There could 

 have been no more appropriate place of meeting in America for 

 the second conference than that of the Harvard College Observ- 

 atory, for Prof. E. C. Pickering's vast organisation of work in 

 all modern branches of astronomy is second to none. 



The conference was presided over alternately by Prof. J. R. 

 Eastman, of the United States Naval Observatory, and Prof. 

 Hale, of the Yerkes Observatory, and the meetings were not 

 only held on August 18, 19 and 20, but were carried over to a 

 series of adjourned meetings held during the course of the 

 subsequent week. 



The papers read were very numerous, and dealt with all 

 kinds of astrophysical work. The work carried on at Harvard 

 formed, perhaps, the chief item in the programme. Some of the 

 papers dealt with were as follows : — 



Prof. George Comstock, on "Some investigations relating to 

 zenith telescope latitudes " ; Dr. Harold Jacoby, on "Photo- 



graphic researches near the pole of the Heavens " ; Mrs, 

 Fleming, on " Stars of the fifth type in the Magellanic clouds," 

 which establishes another connection between these objects and 

 the Milky Way. 



Prof. Solon Bailey presented a paper on "Variable stars in 

 clusters," which is a subject most interesting in the light of 

 recent investigations. 



We notice that general plans for observing the total eclipse of 

 the sun on May 28, 1900, were briefly discussed, and a committee 

 appointed to consider the work of organisation. 



Another important question brought up at the conference was 

 the creation of a permanent astronomical and astrophysical 

 society. This proposal was formally accepted, and a committee, 

 consisting of Profs. Hale, Comstock, Pickering, Newcomb and 

 Morley, w as appointed to consider the organisation. 



THE KNIGHT-DARWIN LAW> 



'X'HE law under the above title is known to botanists through 

 -'- H. Miiller (" Befruchtung der Blumen," Eng. trans., p. 4), 

 who says that Andrew Knight "laid down the law that in no 

 plant does self-fertilisation occur for an unlimited number of 

 generations." This he call's Knight's Law, and later, in sub- 

 stantially the same form, it becomes the Knight-Darwin Law. 

 For the statement of Knight's Law the reader is referred to that 

 author's celebrated paper : '• An account of some experiments 

 on the fecundation of vegetables" (Phil. Trans., 1799). The 

 I words, however, do not occur in Knight's paper, and I imagine 

 that Miiller got them from Charles Darwin's paper on the 

 fertilisation of papilionaceous flowers, where occurs the passage 

 {Gardener's Chronicle, 1858) : " Andrew Knight many years ago 

 propounded the doctrine that no plant self-fertilises itself for a 

 perpetuity of generations." ^ The words are not given in inverted 

 commas, and I strongly suspect that, with a singular lapse of his 

 usual accuracy, my father was merely giving his own interpret- 

 ation of the conclusion which seemed to flow from Knight's 

 expressions when taken with the whole of the context. For in 

 the " Efiects of Cross- and Self-fertilisation," 1876, p. 7, he 

 quotes Knight's actual words. After referring to Sprengel, he 

 goes on : " Andrew Knight saw the truth much more clearly, for 

 he remarks : ' Nature intended that a sexual intercourse should 

 take place between neighbouring plants of the same species ' . . ." 

 and again : " ' Nature has something more in view than that its 

 own proper males should fecundate each blossom.' " Here we 

 have simply the general statement that hermaphrodite flowers are 

 not necessarily self-fertilised ; a statement of fundamental import- 

 ance in floral biology. If the positive statement that " no plant 

 self-fertilises itself for a perpetuity of generations " is to be found 

 elsewhere in Knight's writings, I think Darwin would have 

 quoted it. 



In the "Origin of Species" (edition i., p. 96) he refers to 

 Knight in the following words: "Nevertheless! am strongly 

 inclined to believe that with all hermaphrodites two individuals, 

 either occasionally or habitually, concur for the reproduction of 

 their kind. This view, I may add, was first suggested by 

 Andrew Knight." 



Lastly, in 1868 ("Variation of Animals and Plants," ii. 

 p. 175), after speaking of his own hypothesis, "that it is a law 

 of nature that organic beings shall not fertilise themselves for 

 perpetuity," he adds : "This law was first plainly hinted at in 

 1799, with respect to plants, by Andrew Knight." If he had 

 known any positive expressions — going beyond the nature of a 

 hint — in Knight's writings, would he not have quoted them? 

 It seems, therefore, that, as far as Knight is concerned, the law 

 should be a general statement of the tendency to cross-fertilisation 

 of hermaphrodites, and not the positive statement quoted by 

 Miiller. 



When we pa.ss from Knight's share in the law to Charles 

 Darwin's— there are difficulties in fixing on the most authentic 

 wording of the law. The earliest form is that occurring in the 

 " Origin of Species " (ed. i. p. 97). 



" These facts alone incline me to believe that it is a general 

 law of nature (utterly ignorant though we be of the mean- 

 ing of the law) that no organic being self-fertilises itself for an 

 eternity of generations ; but that a cross with another individual 

 is occasionally— perhaps at very long intervals— indispensable." 



In the sixth edition of the "Origin." 1872, he retains the 

 above passage with the omi.«sion of ihe words "utterly 



1 A paper read before Section K (Botany) at the British Association, 1898. 



2 This sentence is quoted^by Miiller, " Historical Introduction," p. 29. 



NO. I 5 13, VOL. 58] 



