November 5, 1908] 



NATURE 



15 



the disintegration. It will be seen that in many cases 

 the atomic weights of the various products can be 

 deduced. In the succession of products produced by 

 the disintegration of the uranium-radium series, there 

 occur several rayless products and ^-ray products. 

 .Assuming, as is not improbable, that the atomic 

 products undergo an internal rearrangement with- 

 out the expulsion of a mass comparable with the 

 hydrogen atom, we can calculate the atomic weights 

 of the successive products, taking the atomic weight 

 of helium as 4. From the known range of the 

 a particles from uranium and the ionisation it 

 produces compared with the radium associated with 

 it, there is no doubt that uranium expels two o par- 

 ticles to one from radium itself. Whether this is a 

 peculiarity of uranium itself or due to an unseparated 

 product in uranium is not settled. 



Taking the atomic weight of uranium as 238'5, 

 the atomic weights of the different products are as 

 follows : — Uranium X 23o"5, ionium 2305, radium 

 226'5, emanation 2225, radium A 2i8'5> radium B 

 2iS'5, radium C 2i4'5, radium D, E, and F (radio-lead) 

 2io'5, radium .\ (polonium) 2105. It will be seen 

 that the calculated value of the atomic weight of 

 radium is in good agreement with the most recent 

 experimental values. The end product of radium 

 after the transformation of polonium has an atomic 

 weight of 2o6'5 — a value close to that of lead (2o6'9). 

 Boltwood long ago suggested, from examination of 

 the amount of lead in old radio-active minerals, that 

 lead was the probable final product of the disintegra- 

 tion of the uranium-radium series. 



We cannot at the moment apply the same method 

 of calculation to thorium products, for Bronson (Phil. 

 Mag., August, igoS) has recently brought strong evi- 

 dence that the disintegration of the atoms of some of 

 the products is accompanied by the expulsion of more 

 than one a particle. 



In conclusion, it may be of interest to note that 

 the experimental results recorded in this article lead 

 to an experimental proof — if proof be needed — of the 

 correctness of the atomic hypothesis with reference to 

 the discrete structure of matter. The number of 

 a particles expelled from radium can be directly 

 counted, and the corresponding volume of helium 

 determined. In this way it is possible to determine 

 directlv the number of atoms in a cubic centimetre of 

 helium quite independently of any measurements of the 

 charge carried by the a particles. 



E. Rutherford. 



NOTES. 

 The following is a list of the fellows recommended by 

 the president and council of the Royal Society for election 

 into the council for the year 1908-9 : — President, Sir 

 .Archibald Geikie, K.C.B. ; treasurer, Dr. Alfred Bray 

 Kempe ; secretaries. Prof. Joseph Larmor, Prof. John Rose 

 Bradford; foreign secretary. Sir William Crookes ; other 

 members of council. Sir George Howard Darwin, K.C.B. , 

 Prof. J. C. Ewart, Sir David Gill, K.C.B., Dr. J. S. 

 Haldane, Mr. C. T. Heycock, Prof. Horace Lamb, Prof. 

 H. M. Macdonald, Dr. F. W. Mott, Hon. C. A. Parsons, 

 C.B., Prof. W. H. Perkin, Prof. E. B. Poulton, Lieut.- 

 Colonel D. Prain, Sir Arthur W. Rucker, Right Hon. Sir 

 James Stirling, Prof. F. T. Trouton, Mr. W. Whitaker. 



TnF._ Royal Society's medals have this year been 

 adjudicated by the president and council as follows : — The 

 Copley medal to Dr. Alfred Russel Wallace, in recognition 

 of the great value of his numerous contributions to natural 

 history, and of the part he took in working out the theory 

 of the origin of species by natural selection ; the Rumford 



NO. 2036, VOL. 79] 



medal to Prof. H. A. Lorentz, for his investigations in 

 optical and electrical science ; a Royal medal to Prof. John 

 Milne, for his preeminent services in the modern develop- 

 ment of seismological science ; a Royal medal to Dr. Henry 

 Head, for his researches on the relations between the 

 visceral and somatic nerves and on the functions of the 

 afferent nerves ; the Davy medal to Prof. W. A. Tilden, 

 for his discoveries in chemistry, especially on the terpenes 

 and on atomic heats ; the Darwin medal to Prof. August 

 Weismann, for his eminent services in support of the 

 doctrine of evolution by means of natural selection ; the 

 Hughes medal to Prof. Eugen Goldstein, for his discoveries 

 on the nature of electric discharge in rarefied gases. 



M. Philippe van Tieghem has been elected the per- 

 manent secretary of the Paris Academy of Sciences in 

 succession to the late M. Becquerel. 



The International Congress of Geology will be held at 

 Stockholm in 19 10, when it is expected that Baron Gerard 

 de Geer will, on his return from the Arctic regions, read 

 a paper on polar geology. 



A DEPUT.MION from the Incorporated Society for the 

 Destruction of Vermin waited upon Lord Carrington at 

 the offices of the Board of Agriculture on October 29 to 

 request the Government to appoint a coirimission to inquire 

 into the damage to crops done by rats. 



An agreement has been signed by which England and 

 Germany undertake to cooperate in combating the sleep- 

 ing sickness in their East African possessions. The co- 

 operation will take the form chiefly of exchanging reports 

 of cases, and in arranging for the destruction of wild 

 animals which act as " reservoirs," or provide nourish- 

 ment, for the trypanosomes of sleeping sickness. 



A COURSE of twelve lectures — the Swiney lectures on 

 geology — on the geological history of the American fauna 

 will be delivered by Dr. R. F. Scharff in the lecture 

 theatre of the Victoria and Albert Museum, South Kensing- 

 ton, on Mondays, Wednesdays, and Fridays at 5 p.m. 

 The first lecture was given on Monday last, November 2. 

 Admission to the course is free. 



We learn through the British Medical Journal that Prof. 

 Ehlers, of Copenhagen, well known as an authority on 

 leprosy, is now in Paris with the view of organising a 

 scientific expedition to the Danish West Indies, which 

 comprise the islands of St. Thomas, St. John, and Santa 

 Cruz. The object of the expedition is said to be to 

 endeavour to determine the part played by blood-sucking 

 insects, especially fleas and bugs, in the dissemination of 

 leprosy. 



The Bisset Hawkins gold medal of the Royal College of 

 Physicians has been awarded to Sir Shirley Murphy, 

 medical ofiicer of health of the County of London, for his 

 distinguished services in the cause of public health. The 

 FitzPatrick lectures of the college will be delivered on 

 November 5 and 10 by Dr. Leonard Guthrie, on " The 

 History of Neurology," and the Horace Dobell lecture by 

 Mr. Leonard Dudgeon, on November 12, on " The Latent 

 Persistence and the Reactivation of Pathogenic Bacteria 

 in the Body." 



On October 30 Mr. Farman flew, with a machine 

 heavier than air, seventeen miles across country in twenty 

 minutes, from Chalons to a point just outside Rheims. 

 The height of the course of flight was about 150 feet. 

 On October 31 M. Bl^riot made flights across country 

 from his station near Chartres, the longest being one of 



