^So 



NATURE 



[October 3, 1907 



Annce psychologiqiic (vol. xiii., p. 143) a review of the 

 history of the mysterious n-rays from the time when 

 their discovery was first announced by M. Blondlot in 

 1003. A complete bibliography of the subject is appended 

 which comprises in all 176 original papers, very unequally 

 distributed as regards date, nineteen being published in 

 1903. '39 i" 1904 (103 in the first half of the year), seven 

 in 1905, and fifteen in 1906. After the surprising state- 

 ment had been made that it was possible to chloroform 

 metals, and thus, by a process of ana;sthesia, destroy 

 their power of emitting the rays, and largely in con- 

 sequence of Prof. R. W. Wood's letter in Nature (vol. 

 Ixx., p. 530) throwing doubt on the existence of the rays, 

 the lievue scicniijique instituted an inquiry to ascertain 

 whether other physicists who had worked on the subject 

 had succeeded in verifying the remarkable statements 

 made by MM. Blondlot, Charpentier, and Jean Becquerel. 

 This inquiry, which has been briefly referred to in Nature 

 (vol. Ixxi., pp. 113, 132, 157), showed that practically all 

 those who had attempted to establish even the existence 

 of the n-rays had entirely failed. A simple method of 

 settling the question once and for all was then proposed 

 by the Revue scientifique. A number of wooden boxes of 

 exactly the same size and appearance were to be sealed 

 up after enclosing in some of them small pieces of lead, 

 in others rods of tempered steel, the latter being one of 

 the recognised sources of the rays. It was to be left to 

 M. Blondlot or his assistants to ascertain by experi- 

 ments, made in presence of a committee of witnesses, 

 which of the boxes contained the active material. This 

 crucial test was, however, declined by M. Blondlot, who 

 stated that " the phenomena were far too delicate for 

 such a trial," and left "everyone to form his own opinion 

 on the n-rays either from his own experiments or from 

 his confidence in those of others." The subject was thus 

 withdrawn from the region of fact and transferred to that 

 of opinion. It is significant that from this time forward 

 publication of further experiments practically ceased. .\ 

 few attempts were made to obtain photographically 

 objective evidence of the existence of the rays, but these 

 did not withstand the test of criticism. It appears now 

 established that the n-rays and their wonderful effects had 

 no real existence, but that the results published in so 

 long a series of papers were due to illusion caused by 

 a species of auto-suggestion bas»d on preconceived ideas. 

 The matter forms, indeed, one of the most curious 

 chapters, not only m the history of physical science, but 

 also in that of psychology. 



Pages 1-78 of vol. ix. of the Proceedings of the 

 Washington Academy of Sciences contain a very useful 

 compilation, by Mr. James W. McBain, of all the experi- 

 mental data referring to the quantitative measurement of 

 electrolytic migration. Abstracts are given of all papers 

 bearing on the subject between the years 1814 and 1905, 

 the numerical results being summarised in the form of 

 tables. In the introduction a brief discussion is given 

 of the probable degree of accuracy of the determinations, 

 of the errors introduced by the use of diaphragms and 

 by the methods of calculation adopted ; the interpretation 

 of the results is also dealt with, a number of anomalous 

 cases which are not in accord with the prevalent theory 

 of solutions being considered separately, as well as the 

 questions of hydrated and complex ions. The matter is 

 arranged chronologically, but for convenience of reference 

 indexes of substances and authors are appended. The 

 compilation appears to be very complete, and its value 

 is enhanced by the fact that a very large number of the 

 papers bearing on the subject have titles which give no 

 NO. 1979, VOL. 76] 



indication tl)at thi-y contain experiments on electrolytic 

 migration. 



Messrs. J. Grifein and Sons, I,td., have sent us a 

 specimen of their new Bunscn burner, which they call an 



Improved Teclu Burner." The Bunsen, as a matter of 

 fact, is a slightly modified Marshall burner, the chief 

 feature of which was that the air passes up from beneath 

 the burner instead of being drawn in at the sides of the 

 tube. The gas, on the other hand, passes in at the side, 

 and not up the centre. The novelty in the burner is the 

 arrangement for regulating the air supply, which is cone- 

 shaped. We have tested the burner, and find it gives a 

 good non-luminous flame, and can be turned extremely 

 low without striking back. Even when at its lowest the 

 flame is quite non-luminous. 



The new session of the Institution of Mechanical 

 Engineers will be opened on Friday evening, October 18, 

 when a paper on the indicated power and mechanical 

 efficiency of the gas-engine, by Prof. B. Ilopkinson, will 

 be read. 



OVR ASTRONOMICAL COLUMN. 

 New Eleme.nts and Epiiemeris i-or Comet 1907^. — The 

 following set of elements has been calculated for comet 

 1907^ by Herr Kritzinger, from observations made on 

 June 15, July 20, and .August 28: — 



T = 1907 September 3'9792 M.T. Berlin. 

 c» = 294' 21' 377""j 

 ft = i^f 2' 337" •1907-0. 

 ;• = 8° 58' 6- 1" J 

 log y = 9709663. 

 This appears in No. 420.1 of the Astronomische 

 Nachrichien (p. 15, .September 20), and is followed by a 

 daily ephemeris computed therefrom by Herr Spohn ; the 

 following extract gives the calculated positions and magni- 

 tude for every eighth day : — 



Ephemeris i2h. (_M.T. Berlin). 

 1907 a ic)07'o 6 igoy'o log r log .i Mapn"- 



h. m. , , tilde 



Oct. 3 ... II 38-5... -1-3 I7'9 ■•9926s. 0-2458 6-9 



■II ... 12 6-9... -HI 6-3 ... 9-9908 ... 02776 7-4 



19 ... 1231-7... -049-9 ... 0-0472 ... 0-3051 7'8 



27 ... 12 53-6... -230-8 .. 00967 ... 0-3290 81 



Nov. 4 ... 13 13-2 .. -3 58'9 •■■ 0-1399 ..03492 8-5 



The magnitudes are derived from the magnitude at the 

 time of discover)', which is taken as 8^o. 



An ephemeris extending to December 30 is given by 

 Herr J. Franz in No. 4200 of the Astronomische Nach- 

 richien (p. 401. September 12). 



.\n excellent reproduction of Mr. Plaskett's photograph, 

 obtained at Ottawa on July 20, appears as the frontispiece 

 to the current issue of ttie Journal of the Royal Astro- 

 nomical Society of Canada (vol. i.. No. 4). 



September Meteors. — A magnificent bolide was observed 

 at South Kensington by Mr. F. E. Baxandall at 10.40 p.m. 

 on September iq. Its path lay from near Saturn, where it 

 first appeared, to a little south of Cassiopeine, where it 

 was seen to explode and divide into two well-defined por- 

 tions. The object was intensely brilliant, and travelled 

 very slowly along its path of nearly seventy degrees. 



The Electric Action of the Sun and of the Moon. — 

 The results of some experiments on the electric action of 

 the sun and moon, carried out by Dr. Nodon on the 

 summit of the Pic du Midi, appear in No. 12 

 (September 16, p. 521) of the Complcs rendiis, and are 

 exceedingly interesting. Using an aluminium-leaf electro- 

 meter, so insulated th.at a charge of 1500 volts was re- 

 tained for a week, Dr. Nodon found that the sun induced 

 a positive charge, which varied considerably from one 

 moment to another between one and six volts per minute. 

 This charge was completely absorbed by clouds passing 

 before the solar disc, but showed itself when a black card 

 coated with parafTm was interposed between the sun and 



