938 



NATURE 



[December 29, 1923 



for the very wide deviation of the hydrogen chlorine 

 combination from the Einstdn photf>rht»mi<al equi- 

 valence law. Nemst iKwtulat.,! ii it t!,. ) Miliary 

 action of the light was to sphL up ili< . hl-inic into 

 atoms, and that these were able to ri.K t unh ii\<lrogen 

 molecules according to the equation 



C1+H,»HCI 11 

 and tlint the atomic hydrogen i .nn.l nK.iin reacted 

 uit li ( lili)iine 



H+C1,=HC1 ,C1. 



and that this cycle was repeated over and over. 

 Hence i quantum of lif^ht oncrf,^' was nlile to cause 

 a very great animini oi (oiuluii.iiion lie showed 

 that wl these reaclioii-s procuedetl \mUi a free energy 

 decrease and hence were possible reactions. 



We are attempting to put this theory to a direct 

 test. In our experiments atomic hydrogen, generated 

 by Wood's method (Trans. Koy. See, 102-A, i, 1922), 

 is led into a mixture of hydrogen and chlorine, and 

 if the theory is correct an excessively large amount of 

 hydrogen chloride should be formed. To determine 

 the amount of atomic hydrogen at the moment of 

 reaction the same proct'clurf is used substituting 

 bromine for chlorine. It is kiunvn that the hydrogen 

 bromine reaction does not give excessive yields of 

 hydrogen bromide and Nemst has shown that the 

 reaction 



Br+H,=HBr+H 



will not take place spontaneously. Tlie hydrogen 

 and chlorine are at a partial pressure of about i mm. 

 each, and care is taken to prevent illumination of the 

 gas mixture from the discharge tube. It has been 

 shown so far that atomic hydrogen will tra\(l a 

 distance of 15 cm. from the discharge tube wlitn the 

 pressure is i mm. If chlorine be permitted to meet 

 the hydrogen stream at this point direct combination 

 takes place at room temperature ; in one experiment 

 the yield of hydrogen chloride was 10 per cent, of the 

 hydrogen used. This amount would seem to exceed 

 greatly that due to the atomic hydrogen present, 

 although so far no direct determination has been 

 made of this quantity. A. L. Marshall. 



H. S. Taylor. 

 Princeton University, Princeton, New Jersey, 

 November 7. 



Remarkable Ascending Currents at Melbourne. 



Remarkable ascending currents were observed 

 during a pilot balloon ascent at Melbourne at 11.00 

 hours on Friday, October 26, 1923. Heights were 

 determined by means of range-finder readings, and 

 should have no error of consequence. The following 

 table gives the results of the ascent : 



At the first reading the balloon was too near to be 

 observed with the range-finder. The rate of ascent 

 should have been 100 metres in 45 seconds according 

 to J. S. Dines's formula, but for the particular type 

 of balloon used, range-finder observations indicate 



NO. 2826, VOL. 112] 



that 111. actual rate is about 90 metres. Shortly aft- • 

 thr ijlih observation the balloon entere<i thin don 

 but could be seen for some time long< 



Between the second and last rea 

 wJui li ilic balloon was travelling asc< 

 of ( met res per second, while l)etwc< 

 f(jiiM \\ tlir- asrfuflmg velocity was 8 mctrtsi» pur 

 On a nnniIxT (it occasions when cumultis clou 

 forming, ascending rates of 2 metres per second u. : 

 considerable ranges have been observed at Melbourri' , 

 but nothing approaching the velocities shown abo\' 

 had been encountered previously. It will be note 

 that the upward current was at times such that ncj 

 raindrop could descend through it. A remarkable 

 feature was that the cumulus cloud which was forming 

 rapidly at the tinu- was doing so, not in isolated masses, 

 btit in an almost continuous sheet. No cumulo- 

 nimt'iis was jirt^cnt. Above the cumulus layer 

 alto-cuniulu.s \va.s moving from 252'*. 



As regards the general situation, an anticyclone 

 was passing to tihe northwards, moving rapidly. 

 During its passage across the continent tli< 

 cyclone had decreased in intensity. Melboun 

 coming umlcr 'lence of the succeeding low- 



pressure troii- recent weather had been 



characterised by these fast-moving anticyclones, the 

 intervening depressions being ver>' poorly developed. 

 This weather is one of the pronounced drought types. 



Edward Kidso.n. 



Meteorological Bureau, 

 Melbourne, 

 October 29. 



Long Range a- Particles. 



In a letter to Nature of Septembt 

 stated that, in addition to the a-rays of range 0'>7 

 cm., radium active deposit emits particles of range.-. 

 9-3, II-2, and 13-3. cm. respectiveh ' " s since 

 been found that, in addition to the ranges 



4'8 and 8-6 cm., thorium active deposit unms particles 

 of ranges 11-5 (previously recorded by Rutherford), 

 150 and 18-4 cm. respectively, and that the emission 

 of every lo* a-rays of range 8-6 cm. is accompanied 

 by the emission of 220, 47, and 55 particles of the 

 above ranges. In the case of actinium active deposit 

 evidence of particles of range greater than 6-5 cm. 

 was found, but tlie sources available were not 

 sufficiently intense to allow their range to be deter- 

 mined with accuracy. 



By a method devised by Sir Ernest Rutherford we 

 have satisfied ourselves that the long range particles 

 from radium active deposit are a-rays. 



Polonium has also been examined and found to 

 emit small numbers of particles of ranges 6-i±o i, 

 io-o±o-i and 13-1 ±0-2 cm. respectively, in addition 

 to the main group of a-rays of range 393 cm. The 

 relative numbers in these new groups are at present 

 being determined ; from the brightness of the scintil- 

 lations it is considered that they are a-rays. 



L. F". Bates. 

 J. St.\nlev Rogers. 



Cavendish Laboratory, Cambridge, 

 December 15. 



Continental Drift and the Stressing of Africa. 



In replv to Dr. E\ aii> s letter under the above title 

 in Nature of September zi, p. 438, may I say that 

 I too shall be surprised, indeed extremely surprise i, 

 if further work in Uganda does not " disclose tlie 

 existence of at least some normal faulting with a 

 north and south strike, showing the former existence 

 of east and west tension." Compression in one area 

 seems to imply tension in another ; and it is not very 



