August 13, 1903] 



NATURE 



339 



objects. The general study of the solar spectrum has 

 given way to investigations of the sun in detail ; and 

 spectrum analysis now not only reveals the constitution 

 of the stars, but measures their movements with an 

 exactitude impossible by any other means. The light 

 of nebulae has been shown to be but the manifestation 

 of molar activity having a vastly greater sphere of 

 influence than that suggested by the visible limits; 

 and nebulae themselves, from being regarded as a 

 peculiar class of celestial bodies, have been linked to 

 stars and shown to be the amoebae in a scheme of 

 inorganic evolution. 



The story of this development is related by Miss 

 Gierke in the exuberant style with which all readers 

 of astronomical literature are familiar. The first part 

 of her book, occupying about one-third of the whole, 

 is devoted to the sun, and the remainder to sidereal 

 physics. Among the subjects of chapters in the 

 former part are peculiarities of the solar spectrum, 

 the reversing layer, the spectrum of sun-spots, the 

 chromospheric spectrum, the sun's rotation, and the 

 solar cycle. The forty-one chapters of the second part 

 deal with many varieties and characteristics of stars 

 and nebulae, the subjects including helium stars, 

 carbon stars, the spectra of double stars, rotation of 

 the stars, spectroscopic binaries, dark stars, star 

 clusters, nebulous stars, variable nebulae, the nature 

 of nebulae, and the physics of the Milky Way. 



For the collection and anal3sis of contributions to 

 the study of these and other problems in astrophysics, 

 Miss Gierke merits the thanks of astronomers. As 

 is the case with every branch of science in its youth, 

 questions arise much faster than they can be answered, 

 and it requires a fine critical faculty to separate results 

 of transient value from those of significance to scien- 

 tific progress. The historian has to decide what 

 things matter and what may be neglected when con- 

 sidered from the point of view of their influence upon 

 development; and success is achieved when this power 

 of discernment is combined with insight which enables 

 the relationship to be seen between cause and con- 

 sequence. 



With the best desire in the world to give Miss Gierke 

 credit for her work, we must confess to a feeling that 

 it is not altogether satisfactory. In the first place, 

 the net which she has used in her explorations of 

 astronomical literature is of too fine a mesh, so that 

 she has gathered in results and ideas which ought to 

 have been discarded as being of little value, or imma- 

 ture. Next, as we shall show later, she has not under- 

 stood the real nature of some of the material collected ; 

 and finally, she passes judgment and gives advice on 

 matters which can only be rightly understood by in- 

 vestigators actively engaged in spectroscopic work. 



A man who has had a scientific training can quickly 

 grasp the essential. points of progress in any branch 

 of natural knowledge if they are brought before his 

 notice, but he will rarely venture on criticism of 

 results, or lay down the lines of further research 

 unless he has a personal and practical acquaintance 

 with the subject. Miss Gierke does not always 

 exercise the same caution, with the result that she 

 sometimes labours the obvious. Her function as an 

 fiistorian is to assimilate and describe, and when she 

 NO. 1763, VOL. 68J 



is exercising her talents in this direction she is at her 

 best. She surveys the work from the point of view 

 of the spectator, and should describe fairly and clearly 

 what she sees, without irritating the men who are 

 doing the work by expressing her opinion upon it 

 or suggesting what course they ought to take next. 

 In other words, she should remember that " Passen- 

 gers are respectfully requested not to speak to the 

 man at the wheel." 



In preparing a statement of the position of fact and 

 theory in any branch of science, great care must be 

 e.xercised, and not a single assertion should be made 

 without substantial reason for it. A cynic has said 

 that it is a characteristic of women to make rash 

 assertions, and in the absence of contradiction to 

 accept them as true. Miss Gierke is apparently not 

 free from this weakness of her sex. Referring to the 

 line 1474 K she says (p. 117) : — " Eclipse-spectrographs 

 do not include it, while they have afforded some other 

 quite unexpected results." An examination of spec- 

 trum photographs of the eclipses of 1893, 1896, and 

 1898 would have shown Miss Gierke that 1474 K is 

 included in all of them. There are other instances in 

 which statements of an ex cathedra character are made 

 without a full appreciation of the facts. Thus, the 

 identification of a " dozen and upwards " chromo- 

 spheric lines in the spectra of krypton and xenon 

 (p. 120) is doubtful, to say the least; and the Stony- 

 hurst origins referred to on p. 187 in connection with 

 the spectrum of 7 Gassiopeiae are in the same case. 

 Again, in the table of nebular lines on p. 477, the line 

 at A 4122 has a note of interrogation placed after the 

 word helium indicating its origin, though there is 

 practically no doubt that the line is helium x 412 1. 

 Moreover, the line a. 4715, said to be of origin " un- 

 known," is really the helium line A 47I3-3. 



It is in such matters as these that Miss Gierke shows 

 she is not a working spectroscopist possessing an in- 

 timate acquaintance with the subjects she describes. 

 The result is that she is led to pass unsound judg- 

 ments, and to be satisfied with an imperfect record 

 of the facts available. Thus, on p. 48, in considering 

 the relation of the chemistry of the chromosphere to 

 the depth she quotes a paper by Mr. S. A. Mitchell, 

 but makes no reference to the Royal Society report 

 on the 1893 eclipse, where a full discussion of the con- 

 ditions is given. Again, for evidence of the existence 

 of more than one gas in the solar corona reference 

 is made (p. 131) to a paper by Mr. S. J. Brown, but 

 a note on the discussion of the photographs of the 

 1898 eclipse, presented to the Royal Society and pub- 

 lished in the Proceedings (vol. Ixvi. p. 189), is not 

 mentioned, though it shows that three groups of lines, 

 indicating three gases, are recognisable in the corona 

 spectrum. 



Miss Gierke demurs to the late Prof. Rowland's 

 conclusion that there is no fundamental difference 

 between solar and terrestrial chemistry. " Quanti- 

 tative, if not qualitative, dissimilarity must," she 

 believes, " be recognised "; and she instances titanium 

 among other elements which are clearly represented 

 in the solar spectrum, and yet are scarce here. 

 Titanium is more widely distributed than Miss Gierke 

 supposes, but, even if it -were extremely rare, her 



