438 



KNOWLEDGE & SCIENTIFIC NEWS. 



[May, 1906. 



REVIEWS OF BOOKS. 



ASTRONOMY. 

 " Der Bau des Fixsternsystems" (The Structure of the 

 Stellar Universe, with Special Reference to Photometric 

 Results), by Dr. Hermann Kobold, Braunschweig. 

 F. \'ieweg and Sohn ; 6m. 50., pp. xi. + 256, with 3 

 plates and 19 figures in the text).— This is Vol. XI. of the 

 " Wisscnschaft " series of monographs on natural science 

 and mathematics, and must not be regarded as a work of 

 imaginative philosophv. It is an exliaustive collection of 

 methods and results connected with the subject of stellar 

 and solar motion, by no means confined to the photometry 

 emphasised in the title. This is fortunate, for the under- 

 lying assumption in the ordinary photometric method is 

 that brightness and distance are in something like inverse 

 ratio as a rule, and to this the known exceptions are so 

 numerous as to throw great suspicion on the method. Some 

 fortv pages are devoted to instruments and methods of ob- 

 servation, the determination of positions, brightness, colour, 

 spectral tvpe, parallax, proper motion, radial velocity, and 

 distribution of stars, with different light-scales, colour- 

 scales, and spectrum classification, very little being omitted. 

 Then come about 120 pages of separate results, similarly 

 divided and equally complete, from Ptolemy and .^1 Sufi 

 to the twentieth century, with photometric comparison of 

 catalogues, distribution of spectral types, a ver\- interesting 

 table of 43 stars, with parallax greater than i-2oth of a 

 second of arc, giving their computed absolute brightness 

 on a scale in which Sirius is represented by :ooo, the sun 

 by 34, Vega and Capella by more than 4,000, and a Crucis 

 bv about 5,000, and a long section devoted to the solar 

 motion, with a chart showing the results of more than a 

 score of different determinations of the apex, including two 

 by the author, the first of which has been shown to be 

 quite unjustified, the second depending on determinations 

 of radial velocity. It must be admitted that nearly all 

 recent work on this subject emphasises the idea that 

 although the solar system is almost certainly moving to- 

 wards a point not ven.- far from the direction of ^'ega, 

 yet the actual result of investigation is far from satis- 

 factory, inasmuch as eacli different set of stars gives a 

 different position for the apex, e.(j., stars of type 1. give 

 a different result from stars of type II., bright stars a 

 different result from faint stars, and so on ; and although 

 it would seem that stars of large proper motion, or large 

 radial velocity should give a better result, since the effect 

 of small systematic errors is relativelv less in their case, vet 

 the material of this character, being at present restricted in 

 quantity, partly nullifies the advantage. Perhaps, when 

 Herr Ristenpart's great catalogue is completed, a dis- 

 cussion of all available material may give a result that will 

 inspire more confidence. The last sixtv pages of the book 

 are devoted to the " Bau des Fixternsystems," and special 

 care, as usual, is taken to refer everything to the Milky 

 Way, as the basis of the most obvious and plausible hypo- 

 theses. Some good illustrations of the nebuls are given in 

 this connection, especially a fine copv of Wolf's photograph 

 of the " .\merica " nebula in Cygnus, which figures as 

 frontispiece to the book. .At the end we find useful tables, 

 one of 56 stars with well-determined parallax, principallv 

 from the work of Gill, Elkin, and Peter, giving the classifi- 

 cation according to Pickering and Vogel, and in some 

 cases the radial velocity, and the other of 307 stars with 

 proper motion greater than half a second of arc ; which is 

 Porter's list of 301 stars (Cincinnati, Publication No. 14), 

 but corrc'cted and revised, with the addition of six more 

 recent discoveries, including the great southern " run- 

 away," Cardoba, Zone V., 243. Then follow a short biblio- 

 graphy, a useful index, and two large charts of the position 

 of the North and South Poles of the proper motions of the 

 307 stars in the list. As a monograph on the subject, the 

 work is excellent, but no one need adopt any hasty con- 

 clusions from the wealth of material. 



"A la poursuite d'une ombre." Travaux et Observa- 

 tions de la .Societe Astronomique Flammarion de Mont- 

 pellier. Eclipse totale de Soleil du 30 Aout, 1905. — A young 

 Society, founded only in 1902, with an annual subscription 



of five shillings (six francs), has been able to send an ex- 

 pedition of ten members to observe the total eclipse of 1905 

 .August 30, at .Mcala de Chisvert ; a book of nearly a hun- 

 dred pages embodies the result in the form of chatty reports 

 bv Professor Marcel Moye, of Mohtpellier University, one 

 of the secretaries of the Society. Their equipment, as was 

 natural, was far from elaborate, but from the many lines 

 of eclipse work that do not require such equipment, this 

 Society omitted very few, as they carried out on a small 

 scale the careful division of labour now generally associated 

 with a naval detachment under the direction of .Sir Norman 

 Lockyer. In view of the forthcoming volume from the 

 British Astronomical .Association, dealing with the same 

 eclipse, we need not look for anything of unique value in 

 the Montpellier results, and the drawings, as reproduced 

 in the work, have a harsh effect, owing to the too great 

 contrast with the background, suffering much in com- 

 parison with Hansky's 1896 eclipse photograph, also re- 

 produced in the volume. But as evidence of vitality and 

 enthusiasm in a scientific society, we have nothing but 

 praise for the book. 



BOTANY. 

 The Book of the Rothamsted Experiments, by A. D. Hall, 

 M..V. (John Murray ; los. (id. net.) — To every student of 

 agriculture, irrespective of nationality, the mention of 

 Rothamsted recalls to mind the most extended and varied 

 series of experiments, bearing on every branch of agricul- 

 ture, that has hitherto been, or probably ever will be, attempted. 

 Furthermore, the immense amount of information presented 

 in a concise and methodical manner, representing con- 

 tinuous research extended for over half a centurv', and 

 presented to the world at large, will for all time ser\-e as a 

 model, and furnish a sound starting-point for future in- 

 vestigators. 



The primary object of the book under consideration is to 

 present to the student the chief points of importance, and 

 generalisations suggested by the investigations alluded to ; 

 also to indicate the scope and aim of the I^othamsted Experi- 

 ment Station. The result is an unqualified success. There 

 is nothing in the book that cannot be grasped by the farmer 

 or horticulturist taking an intelligent interest in his vocation, 

 whereas to the student and expert its pages teem with valu- 

 able first-hand information, and suggestions for future inves- 

 tigation. 



The entire work is founded on a strictly scientific basis, 

 and deals only with fundamental problems, as indicated by 

 the following extract from the preface : " The farmer who 

 visits Rothamsted must not expect to see demonstrations of 

 the most profitable means of growing this or that crop, but 

 rather to obtain information as to its habits or requirements, 

 which on reflection he can make useful under his own con- 

 ditions." 



Of exceeding interest is the chapter on the sources of the 

 nitrogen of vegetation ; the researches on this subject con- 

 ducted bv Lawes and Gilbert resulted in clearlv demon- 

 strating that the above-ground green parts of plants did not 

 possess the power of fixing nitrogen ; on the other hand these 

 experimenters failed to demonstrate the fact that free 

 nitrogen was fixed bv bacteria present in the nodules on the 

 roots of leguminous plants. This, howe\-er, was not so 

 much due to the fault of the investigators concerned, as to 

 the general apathy towards scientific research in this coun- 

 trv. If the necessarv knowledge had been forthcoming it 

 would have been utilized. This gap, bearing on bacterio- 

 logical work has, so far as Rothamsted is concerned, been 

 bridged by the present Director. 



The generally accepted idea that whole meal of wheat 

 grain is the most nutritive food is fully dealt with, and 

 shown to be wrong. 



From scattered remarks it is gathered that an excess of 

 nitrogenous manure favours the attack of fungus parasites. 



A verv interesting biographical sketch of .Sir John Bennet 

 Lawes and Sir Joseph Henry Gilbert, the founders of the 

 Rothamsted Station, is given. 



CHEMISTRY. 



Qualitative Chemical Analysis (Organic and Inorganic), by F. 



Mollwo Perkin, Fh-D. (Longmans. Green cS: Co. ; vi. -}- 308 pp., 

 5i + 85, 4s., 1905). — The author, who recognises the fact 

 so familiar to teachers of chemistry that students too often 



