March 24, 192 1] 



NATURE 



III 



mond is composed there are four such sub-centres 

 arranged symmetrically — that is to say, in tetra- 

 hedral fashion round the core. 



Must not these sub-centres be electrons? And 

 if so, must we not take them to be circulating- in 

 small orbits about a local centre? Or, perhaps, 

 as Parson has suggested, the electron is ring- 

 shaped, the electricity revolving round the axis 

 of the ring. In this way we should have electro- 

 magnetic forces to link the atoms together. 



It is very interesting to observe that, in any 

 case, the carbon atoms in the diamond are not 

 all oriented in exactly the same way. Taking a 

 cleavage or tetrahedral plane as that of refer- 

 ence, half the atoms will be pointing towards the 

 plane and the other half pointing away. 

 This ought to make a difference to the X-ray 

 spectra, and it has been looked for at various 

 times, but without success. Lately, however, the 

 improvement in the X-ray spectrometer has been 

 considerable, and I now have no difficulty in find- 

 ing the expected effect. ^ It is clear, I think, that 

 the carbon atom in the diamond is to be repre- 

 sented as to its properties by a tetrahedron, and 

 that the atom has different properties in different 

 directions, or, as the chemist would say, has 

 directed valencies. There can be little doubt that 



* There '\9, in fact, a small second-order spectrum in the reflection of X-rays 

 by the tetrahedral plane. 



this is SO in all atoms. The suggestion is that 

 some of the electrons in an atom forming part 

 of a crystal are tied down to certain regions on 

 the surface, and that not all, if indeed any, of 

 them are at all times revolving round the central 

 core. 



When atom joins up to atom it is these sub- 

 centres that are at work ; and since atom to atom 

 and again atom to atom make in the end the 

 crystal, and since the crystalline structure is the 

 basis of all solid structure, and is fundamentally 

 concerned with the strength of materials and their 

 temper and all their physical properties, it is ea.sy 

 to see how great is this minute study of the 

 electron. 



If this conception of fixed electrons seems to 

 clash with the orbital motions of Bohr and Som- 

 merfeld, we must remember that the clash is 

 between two pictures both of which are, we know, 

 imperfect. We may expect that on the next occa- 

 sion when a lecturer tries to tell you what advance 

 has been made in the study of electrons some 

 of these contradictions will have disappeared. 

 Whether it will so turn out or not, I am sure of 

 this, that in the attempt to realise the properties 

 of Nature's unit, the electron, we are working in 

 the true direction towards an understanding of the 

 great problems of radiation and of material 

 structure. 



Reformed Cannibals. 



NEW GUINEA, despite the considerable 

 amount of attention that has been paid to 

 it, has still large areas unexplored, and many 

 peoples about whom nothing is known. Ex- 

 tremely little, even in the " Annual Reports of 

 New Guinea," has been written about the natives 

 of the D'Entrecasteaux group, the large moun- 

 tainous islands which lie off the north coast of the 

 south-eastern end of New Guinea, although a good 

 deal of information has been collected about some 

 of the peoples on the adjacent mainland and about 

 the Trobriand Islanders farther east. An ideal 

 opportunity was thus open to Mr. Jenness, a dis- 

 tinguished classical student of Balliol, who was 

 one of the first to obtain the Oxford diploma in 

 anthropology. A further advantage he had was 

 in the collaboration with his brother-in-law, the 

 Rev. A. Ballantyne, who for nine years had been 

 a missionary on Goodenough Island. 



The result of this partnership is a pleasantly 

 written, sympathetic account of the Goodenough 

 Islanders, which fills up one of the many gaps in 

 our knowledge of the ethnology of New Guinea. 

 The authors have given a succinct account of native 

 life from the economic, social, and psychical points 

 of view, and it is a comfort to students at 

 home to feel that thev have here something on 

 which they can rely implicitly. Specialists will 

 naturally turn to particular chapters, but all 



1 "The Northern D'Entrecasteaux. By T). Jenn'ss and the late Rev. 

 A. Ballantyne With a preface Hy R. R. Marett. Pp. 119. (Oxford: At 

 the Clarendon Press, 1920.) 12J. kd. net. 



NO. 2682, VOL. 107] 



should read the book through in order to get a 

 complete view of the mode of life, actions, ideas, 

 and ideals of the people ; these are all interdepend- 

 ent and cannot satisfactorily be studied apart. 



We may perhaps attribute the conciseness of 

 the book to the present cost of book-production, 

 but a little more detail in various sections would 

 have added to its value. We are, however, given 

 the hope that other matter may be published later ; 

 we trust that this will be the case, and that the 

 material culture will receive fuller treatment, for 

 we learn that the collections have now reached the 

 Pitt-Rivers Museum. We should also like to hear 

 more about the stone sitting-places and their 

 connection with cannibalism, and about the use of 

 memorial- and grave-stones, as these are doubtless 

 connected with one of the great culture migrations 

 into Oceania. Evidently it was not the intention 

 of the authors to enter into the thorny paths of 

 racial or cultural migrations, or even to give 

 parallels among neighbouring people ; so they 

 have rigidly confined themselves to what they have 

 themselves noted, and this is all that we can 

 demand of them. A field-observer who is alive 

 to the wider problems will usually be able to appre- 

 ciate the value of small details which might 

 otherwise be overlooked or considered as too 

 trivial to mention ; but in any case eeneralisation 

 should not be mixed up with description, and our 

 authors have not fallen into this common practice.. 

 The curious custom of chopping off a finger- 



