NA TURE 



[January 



1910 



never searched for nests to believe that one could be 

 found in every bush in which it was sought. It is to 

 be regretted that the author did not put his evidently 

 considerable knowledge of nesting-habits into different 

 form. The succeeding chapter, on curious nesting- 

 places, where the author's experience is told straight- 

 forwardh', is much better. Tlie concluding chapters, 

 on photographing animals and flowers and on protec- 

 tive colouration, are so sketchy as to be of little 

 practical use, and we note some mistakes, e.g. the 

 statement on p. 161 about the cause of colour differ- 

 ences in moths probably has no foundation. 



The style of the whole book is colloquial, and some- 

 times marred by not very successful attempts at wit. 



The book is illustrated by a number of very pretty 

 photographs, which are distinctly good, but not of 

 the striking character made familiar by some other 

 nature-photography works. Nearly all are stereo- 

 scopic, and a stereoscope is supplied with the book 

 which adds considerably to their usefulness. Unfor- 

 tunately, the stereoscope makes the texture of the 

 process-block unpleasantly conspicuous. Although the 

 photographs are not especially striking, they illustrate 

 well the kind of work which an amateur who is 

 limited in time or means may hope to produce. 



TRI. }iB.W COMET (1910a). 

 ''pHE comet discovered near Johannesburg on 



•'• January 16, as announced in last week's 

 Nature, has justified the opinion then expressed as 

 to its becoming a brilliant object in our evening 

 slcies. From many parts of the civilised world we 

 hear of crowds gathering to watch the rare pheno- 

 menon, and the daily Press, despite the General 

 Election excitement, has devoted considerable space 

 to the description of the " Daylight Comet." 



.Apparently the comet was first seen by some miners 

 on January 16, and reported to Mr. Innes, of the 

 Transvaal Observatory, Johannesburg. Messrs. 

 Worssell and Innes made the first measurement of its 

 position at igh. 29'2m. G.M.T. January 16, that 

 is, at g.29 a.m. on January 17 local standard time, 

 when the sun would be well above the horizon. The 

 measures were continued until January 17, oh. 8'6m. 

 (Johannesburg M.T.), that is, midday, and thev 

 showed that the comet was rapidly approaching the 

 sun, the apparent movement per hour being +42S. in 

 R.A. and -l-6'5' in declination. 



Mr. Innes described the comet as having a head 

 5' in diameter, and a well-developed tail ; in a later 

 message the latter, was stated to be 1° long, fan- 

 shaped, and visible to the naked eye. This observa- 

 tion emphasises the e.xceptional brilliance of the comet 

 and the purity of the Transvaal atmosphere, for at 

 the time of observation the comet was within 45° of 

 the sun and went of it. 



The apparent motion was so rapid that by the 

 time the discovery was announced here the comet 

 had passed to the east of the sun, and was therefore 

 to be seen at or after sunset instead of before or at 

 sunrise. The Cambridge Observatory appears to have 

 been the most fortunately situated of English observa- 

 tories, for the sky was clear enough on January 19 

 to warrant an attack in force, and Mr. Hubrecht was, 

 according to Saturday's Daily Mail, fortunate enough 

 to find the comet straight away. Mr. Hinks there- 

 upon secured a measure of the position, and saw a 

 nucleus as bright as Mercury, and a tail 2° long ; on 

 Thursday, January 20, the nucleus was seen to be 

 brighter and the tail further developed. 



According to a Central News correspondent, the 

 comet was seen, in full daylight, at the Milan 

 Observatory, but no tail was seen. The observations 

 NO. 2100, VOL. 82] 



of the tail vary considerably in their estimates of its 

 length, but this is to be expected, for, obviously, the 

 prominence of such a filmy structure in davlight or 

 twilight will vary greatly with the purity of the 

 atmosphere. 



.'Vt Oxford, Prof. Turner found the comet quite a 

 conspicuous object, in field-glasses, at 5 p.m. on 

 January 20, and could see it quite easily with the 

 naked eye ; he made his observations from the Robin- 

 son Tower of New College. 



On Friday, January 21, the Cambridge observers 

 were again favoured, and, according to th \ Times, 

 Mr. Hinks found the comet to be considerably brighter 

 than on the preceding day, and to have a fine stellar 

 nucleus with the surrounding envelopes well 

 developed. Prof. Dyson, at the Royal Observatorv, 

 Edinburgh, also saw the nucleus. The same day, Mr. 

 J. H. Elgie, observing at Leeds, saw the comet at 

 5 p.m., and describes it as "weirdly magnificent," 

 having a tail 8° long. The nucleus, he estimated, 

 was as bright as Mars at the recent opposition, and 

 the tail was curved, with the concave side towards 

 Venus; the outer edge was then well defined, but 

 further observations, on Saturday, showed it to be 

 much more diffused. The Rev. F. J. Jervis-Smith, 

 writing from Lymington, says that several persons 

 observing there on January 22 thought the tail ap- 

 peared to flash slightly and continuously, but this 

 phenomenon may have been due to the low position of 

 the object and consequent atmospheric effects. 



The lengthy reports in Monday's Times, Daily 

 Mail, Chronicle, Skc, show that the comet was well 

 observed during the week-end. On Saturday, January 

 22, Prof. Turner secured two photographs showing 

 the brighter portions of the tail, and four photo- 

 graphs were taken at the Dunsink Observatory. Dr. 

 Whittaker and his assistants at Dunsink also observed 

 the comet visually, and found that, in addition to the 

 tail, extending upwards to a distance of 8°, where 

 it was lost in a dense cloud, there was a distinct jet, 

 or horn, of light on that side of the head nearest to 

 the horizon. The head of the comet appeared as a 

 dusky-red nucleus surrounded by a nebulous envelope 

 of fainter red, and was as large as, or larger than, 

 Mars. The twin tails were of a bright yellow colour. 



Dr. Rambaut observed the comet with the 10-inch 

 and 18-inch telescopes at the Raddiffe Observatory 

 on January 22, and saw it quite well, despite a thick 

 haze. Prof. Dyson also made observations at Edin- 

 burgh, and found, at 5.25 p.m., that the head was 

 as bright as Mars and had a nucleus 45" in 

 diameter, whilst the tail extended to a distance of 7°. 

 \t Cambrid "e it was estimated to be 6° long. The 

 orbit computed by Messrs. Stratton and Hubrecht, at 

 Cambridge, shows that the comet passed through 

 perihelion on January 17, at a distance of two million 

 miles from the sun, and will continue to move north- 

 wards with diminishing speed. 



.'\t the Solar Physics Observatory, South Kensington, 

 and, we understand, at the Royal Observatory, Green- 

 wich, the careful preparations for observing, and the 

 constant attendance of the staff during the hours 

 available for observations, were, until Tuesday even- 

 ing, rendered nugatory by clouds, or by the per- 

 sistent smoky haze which, even on Saturday, rendered 

 Venus a faint object, and made quite hopeless the 

 careful search for the comet. But on Tuesday even- 

 ing observations were secured by Dr. W. J. S. Lock- 

 yer, using the lo-inch refractor, and these showed 

 that, at 5.35 p.m., the Kiel position was in error to 

 a slight extent in R..'\. and about 2° in declination, 

 the observed place being further south than that indi- 

 cated by the ephemeris. 



In a telegram transmitted by Prof. Pickering to the 



