6.^2 



NA TURE 



[October 25, 1906 



(been an arduous worker at this branch of science, 

 and it will be convenient to have in a compact form 

 the outcome of his numerous fuller publications, 

 which it is the object of this book to present. Prof, 

 l^oeb's name is best known in connection with tl..? 

 parthenogenesis which he has artificially produced in 

 unfertilised marine eggs, by altering the saline con- 

 stituents and other physical conditions of the surround- 

 ing water. This subject is here given in its most 

 recent developments, but the book naturally contains 

 a good deal in addition. We may regard the work 

 as a useful counterblast to those who term themselves 

 neo-vitalists. It can hardly be considered the last 

 word on the subject. Physical chemistry in relation to 

 inorganic material is in a state of f^ux, one theory 

 displacing others with startling rapidity. It is, there- 

 fore, a little early to apply it to organic and living 

 substances with any hope of obtaining universal 

 acceptance of the theories put forward. The specula- 

 tions indulged in are interesting, and the facts will 

 settle down into their proper places later on. 



The third book in this physiological batch relates 

 to a small corner of physiological inquiry, namely, 

 taste and smell, and mainly the former. Dr. Stern- 

 berg has devoted attention to this sub-branch of a 

 branch of physiology, and has produced a readable 

 pamphlet. It is, however, a little difficult to under- 

 stand why books should be written with such limited 

 scope, and it is doubtful if they are really needed. 



MATTER .l.Y/) RADIO-ACTIVITY. 



The Electrical Nature nj Matter and Radio-activity. 

 By Prof. Harry C. Jones. Pp. i.K + 212. (London: 

 Archibald Constable and Co., Ltd., 1906.) Price 

 ys. 6d. net. 



THI.S book consists of a series of articles, written 

 in semi-popular style, reprinted from the 

 Electrical Review. The first third of the book is 

 occupied with the electronic theory of matter, and 

 follows the usual popular lines. The subject is treated 

 only from what may be called the Cavendish Labor- 

 atory point of view, and, in fact, we read that we owe 

 the whole electronic conception to Prof. J. J. 

 Thomson. The optical and spectroscopic foundations 

 for the theory are omitted, and the names of Larmor, 

 H. A. Lorentz, and Zeeman are not mentioned. 



It is difficult to attempt to review this part of the 

 book, for if the reviewer has interpreted a recent 

 paper by Prof. J. J. Thomson aright, the view that 

 the constituent electrons of an atom are present in 

 sufficient numbers to contribute any appreciable part 

 of its mass appears to have been disproved. Here, 

 however, we read : — 



" There is one point at least brought out so clearly 

 that there can scarcely be any question about it, and 

 that is that matter is a pure hypothesis." 



And again : — 



" The atom according to this theory is very 

 ■complex. Take, for example, the atom of mercury. 



NO. 1930, VOL. 74] 



This contains somewhat more than 150,000 electrons, 

 and some of the heavier atoms are even more 

 complex." 



The author, by thus presenting so dogmatically 

 and literally the speculations which have centred 

 around the electron as the basis of matter, has 

 directed attention away from the solid experimental 

 work on which our knowledge of the nature of 

 electrons rests. It is this work, and not the sweeping 

 electronic hypothesis, which is connected with radio- 

 activity. But for the pioneer work on the ionisation 

 of gases done in the Cavendish Laboratory and else- 

 where, the electrical method of radio-active measure- 

 ment could not have reached its present perfection, 

 and it is safe to say that, deprived of this method, 

 radio-activity would have advanced but slowly. But 

 whether the atom of mercury has 200 or 150,000 

 electrons is a question which fortunately has nothing 

 to do with the very fundamental and independent 

 conclusions of the nature of matter formed from 

 radio-active evidence. 



Radio-activity, the second topic, is started in 

 chapter v., and with the remainder of the work and 

 the mode of treatment no exception can be taken, 

 except that it is not very up-to-date. The last 

 chapter, which is entitled " Most Recent Work in 

 Radio-activity," attempts, however, to accomplish 

 this. 



The book as a whole gives a comprehensive and 

 interesting survey of the radio-activity of matter as 

 it is interpreted by the disintegration hypothesis. 

 Perhaps the best chapters are those dealing with the 

 reproduction of radio-active matter and the theory 

 arising therefrom. Here the chemical training and 

 point of view of the author are in evidence, and the 

 significance of the continuous reappearance of the 

 products of change after complete removal by 

 chemical or other means is very clearly brought out. 



Attention may be directed to some inaccuracies and 

 errors of minor importance. The author does not 

 seem very clear about the nature and properties of 

 the 7 rays. We learn that their power to affect the 

 photographic plate is much greater than that of the 

 or even the a particles, an error which is frequently 

 repeated. Their origin is ascribed to the impact of 

 /3 rays on solid matter ratfier than to the acceleration 

 of the P particle during expulsion. In the experi- 

 ment of causing, by means of a glass tube containing 

 radium, a discharge to pass between two points just 

 so far apart that ordinarily the spark fails, most of 

 the ionisation from the glass tube is ascribed to the 

 y ravs. It is safe to say that if the glass were as 

 thick as this the experiment would fail. The state- 

 ment that the emanation can be condensed at low 

 temperatures like an ordinary gas into a liquid is 

 obviously a slip, for a little later we read that no liquid 

 or even mist will be seen. Twice later, however, the 

 statement is repeated, and liquid appears a loose 

 word for non-gaseous. The /3 rays are ascribed little 

 power of exciting phosphorescence, and the effect on 

 a platino-cyanide screen is said to be greater for a 

 than for /3 and 7 rays. F. S. 



