February 3, 1910J 



NA rURE 



417 



Setting out the known elements in the order of the 

 numerical value of their atomic weights, we find that 

 between the first three elements, H=i, He = 4, and Li = 7, 

 the difference, 3, is greater than would be expected by 

 comparison with the differences noticed between the 

 elements of greater atomic weight which immediately follow 

 them. In order to satisfy the hypothesis just put forward, 

 there appears to be wanting an element which should stand 

 in the same relation to fluorine as hydrogen to lithium. 

 This would have an atomic weight 2-7 approximately. 

 Whether this e.xists, and whether its existence is indicated 

 by the unappropriated spectral lines of nebute or corona, 

 can only be a matter of conjecture. MendeliSeff, in his 

 (1905) latest speculations concerning the possibility of still 

 undiscovered elements, has suggested the existence of a 

 new element of the halogen group with an atomic weight 

 about 3 ; ' but, as already sufficiently shown, he accepted 

 no hypothesis which involved any idea of the composite 

 nature of the elements. It would therefore have been 

 foreign to his system to employ this element in any such 

 manner. 



The conceptions presented to us in J. J. Thomson's 

 work permit of several supplementary hypotheses, especially 

 the idea that if «toms are really made up of smaller cor- 

 puscles these are not thrown together in confusion, but, 

 as he has shown, must be distributed within the mass in 

 a definite order, which is determined by the attraction of 

 the electro-positive shell and the self-repulsion of the 

 negative corpuscles included in it. Once the idea of struc- 

 ture within the atom is admitted, the possibility presents 

 itself of there being for the same mass more than one 

 arrangement corresponding to what is called isomerism in 

 compounds. 



I have dwelt at some length on these various hypotheses, 

 because the discussion of the subject to which they relate 

 indicates, in my opinion, one of the consequences of the 

 promulgation and general acceptance of the periodic scheme 

 of the elements. This is, however, not the only result 

 of the recognition of its validity and usefulness by chemists 

 generally. That the elements stand in a definite relation 

 to one another implies that their compounds also fall into 

 their places in an orderly system, and consequently a 

 basis is provided for the complete systematisation of the 

 whole science of chemistry. There is scarcely a treatise 

 on chemistry which does not bear evident witness to this 

 influence ; and this is perhaps not the least among the 

 services rendered by this generalisation, for not only is 

 the learner enabled to remember a much larger number of 

 facts than previously, but he is led to perceive a connec- 

 tion between phenomena and processes which was almost 

 entirely wanting so long as practical chemistry consisted 

 mainly of a bundle of recipes. Here it is fitting that 

 we should glance at tiie famous treatise by Mendel^eff 

 himself, "'Ihe Principles of Chemistry," of which we 

 possess three editions in English, the last of which, issued 

 in 1905, is a rendering of the seventh edition (1903) of the 

 original. An eightli Russian edition began to be issued in 

 1905, but is incomplete. To this remarkable book it is 

 impossible to do justice in a brief notice or to communi- 

 cate to those who have not read it an adequate impression. 

 Clearly it is a work of genius, but such works are not 

 always the most suitable for beginners, though for the 

 advanced student nothing can be more inspiring. The 

 " Principles " embody in reality two distinct treatises, for 

 the text, which is written in an easy style, open to quite 

 straightforward reading, is accompanied by notes which are 

 often more voluminous and usurp entire pages. Even the 

 preface is attended by these commentaries, which are all 

 interesting as showing the spirit of the writer and the 

 restless activity of his mind. 



Little more remains to be said. In the seventeenth 

 century Robert Boyle taught us how to distinguish elements 

 from compounds, and how to give to the word " element " 

 a definite connotation clearly distinguishing it from the 

 elusive and fantastic language of the alchemists. In the 

 eighteenth century Lavoisier showed the true nature of 

 the most familiar of chemical compounds, namely, acids, 

 bases, and salts, and helped to lay the foundation of 



^ It may also, perhaps, be worthy of note that Mr. Kgenon's calculations 

 (/rr. c.'V.) lead him to postulate an eltment of nearly this atomic weight, 

 namely, a'9S44, although his paper gives no indication as to its character. 



NO. 2I0I, VOL. 82] 



quantitative chemistry. At the beginning of the nineteenth 

 century Dalton gave to chemistry the atomic theory, of 

 which it is not too much to say that it provided the scaffold 

 by the aid of which the entire fabric of modern theoretical 

 cheinistry has been built up. Sixty years later this concep- 

 tion, developed and adorned by the labours of an army of 

 earnest workers, has been shown to us in a brilliant new 

 light thrown over the whole theory by MendeMeff. 



The views of Boyle, of Lavoisier, and of Dalton have 

 been corrected by experience and broadened by extended 

 knowledge, but the fundamental and essential parts of 

 their ideas remain, and their names are immortal. In like 

 manner the expression of the periodic law of the elements 

 as known to the present generation is destined, we may 

 believe, to be absorbed into a more comprehensive scheme 

 by which obscurities and anomalies will be cleared away, 

 the true relations of all the elements to one another re- 

 vealed, and doubts as to the doctrine of evolution resolved 

 in one sense or the other ; but as with the atomic theory 

 itself, there is no reason to doubt that the essential features 

 of the periodic scheme will be clearly distinguished through 

 all time, and in association with it the name of MendeldefT 

 will be for ever preserved among the fathers or founders 

 of chemistry. 



UNIVERSITY AND EDUCATIONAL . 

 INTELLIGENCE. 



C.-VMBRiDGE. — Mr. C. Forster Cooper has been appointed 

 demonstrator of animal morphology by the professor of 

 zoology and comparative anatomy for five years from 

 Christmas, igog. 



Dr. Hobson has been appointed chairman of the 

 examiners for the mathematical tripos, part ii. (new 

 regulations), 1910. 



The special board for physics and chemistry has appointed 

 Mr. F. W. Dootson as assessor in chemistry to the 

 examiners for the mechanical sciences tripos in igio. 



The Quick professor of biology commenced on Feb- 

 ruary 2 six lectures on the pathogenic Protozoa, to be 

 given on Wednesdays and Fridays. Attendance is free to 

 members of the University. There will be two lectures on 

 February 23 and 25 on " Recent Progress in the Treatment 

 of Protozoal Diseases." These two lectures will be free 

 to all desiring to attend. 



The chairman of the board of anthropological studies 

 gives notice that Mr. Roscoe's lectures on the natives of 

 Uganda will be given on Tuesdays, at 5 p.m., in the 

 archaeological museum. 



Durham. — The University this term comes under the 

 operation of a new constitution established by an un- 

 opposed Act of Parliament last session. Originally the 

 effective control of this University rested with the Dean 

 and Chapter of Durham, who founded it, but gradually, 

 after the incorporation of the Newcastle College of Medicine 

 in 1852 and the establishment of the Durham College of 

 Science, now Armstrong College, in Newcastle, actual 

 power passed into the hands of an academic body, the 

 Senate. This body, showing the anomalies of its growth, 

 lately left much to be desired in representing a balance 

 among the interests involved. Fortunately, the interests 

 were not really competitive, and a solution has been found 

 by consent. The Durham colleges retain their original 

 endowments, and remain constituent colleges on the model 

 of the old universities. A new Senate is established, 

 elected in equal shares from Durham and Newcastle, which 

 assigns the conditions for graduation, while each division 

 is at liberty to propose for the approval of the Senate in- 

 dependent courses for the same degree. Thus the degree 

 of B.A., which has hitherto been reserved to students from 

 the Durham colleges, will now be open to students from 

 Newcastle as soon as an approved course is established, 

 and it is hoped that this will lead to a considerable develop- 

 ment of .Armstrong College upon the arts side, hitherto 

 much stunted in comparison with its equipment for science. 

 The first Vice-Chancellor, appointed on January 25, is Dr. 

 F. B. Jevons, the well-known principal of Hatfield Hall, in 

 Durham. It is much regretted that Sir Isambard Owen, 

 to whose tact the success of the negotiations is largely due, 

 is removed from participation in the first steps of the 



