50 



KNOWLEDGE. 



[Makch 1, 1808. 



especially at or near the time of minimum — was very 

 apparent on the present occasion. 



The photographs of the corona have been unusually 



The Sun's Corona, Total Eclipse, January 22nd, 1898. 



numerous, and have been taken on every variety of scale, 

 from a diameter of a single millimt'tre with a hand camera, 

 up to one a hundred times as great. The latter were 

 obtained at three stations ; by the Astronomer Royal at 

 Sahdol, with an aperture of nine inches and an enlarging 

 lens ; by Dr. Copeland, at Gogra, near Nagpur ; and by 

 Prof. W. W. Campbell at Jeur, with telescopes of about 

 forty feet focal length. Next in order to these giant 

 photographs come the standard instruments of the Joint 

 Eclipse Committee, with their twin cameras giving images 

 of an inch and a-half, and of six-tenths of an inch. These 

 were employed by Prof. Turner at Sahdol, and Captain 

 Hills at Pulgaon. The cameras taking photographs of one 

 inch in diameter and smaller were much too numerous 

 to recount ; but special note should be made of Prof. 

 Burckhalter's device for obtaining both the inner and 

 outer corona on the same plate by means of a revolving 

 screen worked by a spindle passing through a hole in the 

 centre of the plate, which diminished the exposure given 

 to the bright central regions of the corona so as to bring 

 it more in accord with the faint light of the outer 

 extensions. 



At the extreme ends of the line of stations a novel 

 experiment in coronal photography was attempted. At 

 Buxar, on the Ganges, and at Viziadrug on the coast, 

 a kinematograph was employed so as to obtain a con- 

 tinuous series of photographs of the progress of the 

 eclipse. The former instrument was supplied by Mr. 

 Nevil Maskelyne, and was worked by the Rev. J. M. 

 Bacon, the astronomer in charge of one of the two parties 

 organized by the British Astronomical Association, and 

 the other was in the hands of Lord Graham. 



Of direct visual spectroscopic observations there were 

 few. Mr. NewaU and myself endeavoured to trace the 

 distribution of coronium — that is, of the substance which 

 shows its presence in the 1474 K line ; but the line was 

 faint, and it could only be ascertained that it showed a 

 general conformity to the shape of the brighter part of the 



inner corona, without its being possible to ascertain 

 whether it corresponded in minuteness of structural detail. 

 No rifts were detected in it. 



The photographs of the spectrum claim the highest 

 interest, and these were of unprecedented number and 

 value. Captain Hills, at Pulgaon, with two great slit 

 spectroscopes, obtained records of the "flash," both at 

 commencement and end of totality, which give a complete 

 history of the spectroscopic changes seen in the various 

 strata of the sun, from its ordinary spectrum up to that 

 of the prominences at Viziadrug on the coast. Mr. Fowler 

 and Dr. Lockyer were equally successful with prismatic 

 cameras of six inches and nine inches aperture, whilst 

 smaller spectrographs of extreme beauty, and ranging from 

 C in the red far into the ultra-violet, were secured by 

 Mr. Evershed at Talni. 



The examination and interpretation of these photo- 

 graphs will be the work, not of days and weeks, but of 

 months, and possibly years ; but we may confidently look 

 to them for a complete answer to many questions which 

 are engaging the attention of solar physicists at the 

 present time, and particularly for information as to the 

 exact /()('((/(■ of the absorbing vapours which give rise 

 to the Fraunhofer lines. Sir Norman Lockyer's theories, 

 in particular of dissociation in solar and stellar atmo- 

 spheres, will be put to the severest test, and our know- 

 ledge of solar mechanism can hardly fail to receive a great 

 advance. 



One inquiry which it was hoped the present eclipse 

 would advance has failed to meet with success. Mr. 

 NewaU was endeavouring to ascertain if the spectrum of 

 the corona, as obtained from the two opposite Umbs of the 

 sun, gave any evidence of relative motion in the line of 

 sight due to rotation. It will be remembered that in 1893 

 M. Deslandres came to the conclusion that the corona 

 rotated in essentially the same period as the photosphere. 

 Mr. Newall had arranged an exceedingly beautiful instru- 

 ment for this purpose — a spectroscope, the collimator new 

 telescope of which was parallel to the polar axis. The 

 spectroscope was also provided with a double slit, the one 

 slit tangential to one limb, and the second to the other 

 limb ; the one slit stretching from the sun's equator 

 northward, the other from the opposite end of the equator 

 southward. The experiment, which abundantly deserved 

 to succeed, was, however, frustrated by the faintness of 

 the coronal spectrum. 



Of other observations it is scarcely possible to speak as 

 yet. It should, however, be added that the polariscope, 

 which has been almost forgotten in eclipse work for the 

 last fourteen or fifteen years, was very successfully used, 

 both at Sahdol and at Pulgaon, and the clearest indications 

 were secured of strong radial polarization. 



Such is a very brief outline of the principal results (so 

 far as we yet know them) of this the most completely 

 successful eclipse on record. We hope to be able, at no 

 very distant date, to go much further into detail, when 

 some portion of the photographs obtained have been deci- 

 phered and discussed. 



BRITISH BEES.-I. 



By Fred. Exock, f.l.s., f.e.s., etc. 



THE number of species of bees in Great Britain is 

 by no means large — only just over two hundred — 

 and yet to those people who, " having eyes, see 

 not," this small number is far too large for insects 

 which possess stings. Gardeners, too, look upon 

 them as marauding thieves, and this in spite of the fact 



