174 



NA TURE 



[June 25, 1908 



mathematics." What was to be done? Lord Dun- 

 raven tells us that he does not pretend to be a master 

 of any of these subjects, but he was determined that 

 his book should do for the extra masters of the 

 future what it had done for those in the past, so hp 

 heroically mastered the necessary amount of informa- 

 tion, increased his book to three volumes, and brought 

 it up to date. 



We have no hesitation in saying that the same 

 capacity for imparting the precise information which 

 characterised the earlier edition is equally noticeable 

 in this. The arrangement of the contents is not 

 materially different. In the first volume we have a 

 good deal of elementary preparation that ought to 

 have been acquired in school, and some technical 

 problems, including the use of the compass under 

 various conditions and a review of the law of storms. 

 The second volume is more particularly devoted to 

 the problems of nautical astronomy, which are neces- 

 sary in order to obtain a master's certificate. In the 

 third volume we climb to that dazzling height the at- 

 tainment of which entitles the ambitious plodder to the 

 coveted " blue ticket "of an extra master. There are 

 not only a great many examples given the working 

 of which would be advantageous, but many useful 

 hints that it would be unwise for the intending candi- 

 date to neglect. 



The Loudon Catalogue of British Plants. Tenth 

 edition. By F. J. Hanbury. Pp. 4S. (London : 

 George Bell and Sons, 1908.) Price gd. 

 Since the ninth edition of the " London Catalogue " 

 was published in 1895, important events in connection 

 with the nomenclature of British plants have oc- 

 curred, .^t the Vienna congress, rules with regard to 

 priority and other matters were framed, and hardly less 

 important for the " London Catalogue " was the pub- 

 lication of the ninth edition of Babington's manual 

 and other special works on British plants. The chief 

 credit for the present revision is assigned to Mr. 

 W. A. Clarke and tlie Rev. E. S. Marshall, but 

 various specialists have contributed revisions of genera 

 or sections. The number of plants enumerated in 

 the " Catalogue " is appreciably greater than the list 

 issued from the Natural History Museum, since, 

 according to the preface, it aims at providing a useful 

 working list. Although both lists are compiled on 

 similar lines, it will be found that .the species under 

 critical genera, such as Ranunculus, do not coincide, 

 whence it need only be concluded that e.xperts still 

 agree to differ. 



Jahrbitch der Naiurivisscnschaftoi, 1907-1908. Edited 

 by Dr. Max Wildermann. Pp. xii + 5og. (Frei- 

 burg : Herdersche Verlagshandlung, 1908.) Price 

 7'5o marks. 



This is the twenty-third issue of a year-book in which 

 progress in various branches of science is described in 

 a series of articles by different authors, with references 

 to the original publications abstracted. The subjects 

 are dealt with under (i) physics; (2) chemistry; (3) 

 astronomy ; (4) meteorology ; (5) anthropology, ethno- 

 logy, and archeology ; (6) mineralogy and geology ; 

 (7) zoology; (8) botany; (9) forestry and agriculture; 

 (10) geography; (11) hygiene and medicine; (12) ap- 

 plied mechanics; (13) technology; (14) miscellaneous 

 reports. In addition, the volume contains summaries 

 of celestial phenomena observable from May i, 1908, 

 to May I, 1909, short obituary notices of men of science 

 deceased in the year surveyed, and an author-and- 

 subject index. 



The volume should be of service as a general record 

 of scientific work of which accounts have appeared in 

 periodicals and the publications of societies. 



NO. 2017, VOL. 78] 



LETTERS TO THE EDITOR. 



[The Editor does not hold himself responsible for opinions 

 expressed by his correspondents. Neitlier can he undertalie 

 to return, or to correspond with the writers of, rejected 

 manuscripts intended for this or any other part of Nature. 

 No notice is taken of anonymotis communications.] 



Prominence and Coronal Structure. 



In a paper communicated to the Royal Society in 

 December last (Roy. Soc. Proc, A, vol. Ixxx., p. 178), an 

 abstract of which appeared in this journal (vol. Ixxvii., 

 p. 314, .April 2), I directed attention to a peculiar form of 

 prominence which had been photographed with the spectro- 

 heliograph of the Solar Physics Observatory in the " K " 

 light of calcium. This prominence, situated towards the 

 south pole of the sun in the eastern quadrant, about 

 position-angle 137°, was recorded on two separate negatives 

 taken at the times 3h. 14m. p.m. and 3h. 50m. p.m. 

 G.M.T. on July 17, 1C107. .-Mthough on each photograph 

 inrages of other prominences were recorded, no particular 

 attention was directed to them, as they did not present 

 any unusual features. It may, however, be incidentally 

 remarked that the most intense prominence recorded on 

 both the photographs, and situated near the south pole 

 in the western quadrant about position-angle 218°, was 

 reproduced in the paper in Plate iii., Fig. 5. I did not 



Fig. I. — The prominences on the Sun's limb photographed in calcium 

 light on July 17, 1907, 3h. i4ni. p.m. G.M.T., at South Kensington. 



thinlc it necessary for the purpose of that communication 

 to reproduce the whole limb of the sun, but confined 

 myself to the disturbed area in the south-eastern quadrant. 

 The presence of a large prominence in the south-western 

 quadrant has raised questions of identity, so the complete 

 limb is now here reproduced (Fig. i) to show the relation- 

 ship between the two prominences and the sun's south 

 pole. 



In April last I received from Mr. Philip Fox, of the 

 Yerkes Observatory, U.S.A., a communication in which 

 he wrote : — 



" The large prominence which you discuss certainly has 

 curious form. I have examined my plates for July 17, 

 1907, and find no prominence of unusual form near the 

 south pole in the eastern quadrant, but there is a beautiful 

 one near the pole in the western quadrant at position- 

 angle 215°. I am wondering if by chance you have given 

 the wrong quadrant and if our prominences are identical. 

 I made my exposure at 5h. s6m. p.m. G.M.T." 



On both the Kensington negatives there is a large 

 prominence in the south-western quadrant at about 

 position-angle 218°, and it is intense and shows little 

 indication of diminution iji brightness. This is, no doubt, 

 the prominence referred to by Mr. Fox, who gives 215° 



