NA TURE 



j^OCTOBER 4, 1906 



.ished in 1891, Boltzmann makes use, not only of 

 nionocycles, but also of what he calls ''bicycles," 

 illustrating the phenomena of mutual induction of 

 electric currents. 



In 1885 Boltzmann was raised from " correspond- 

 ing " to ordinary member of the Vienna Academy. 

 He remained at Graz until about 1891, when he was 

 called to Munich. A year or two later he visited 

 England and called on the present writer at Cam- 

 bridge, and thus a personal friendship sprang up. 

 In 1894 the British Association meeting at Oxford, 

 with its memorable field-dav on the kinetic theory, 

 came simultaneously with 'Lord Ra\ leigh and Sir 

 William Ramsay's announcement of the discovery of 

 argon. _ The part which Prof. Boltzmann took in 

 these discussions will long be remembered. He re- 

 ceived an honorarv degree, and expressed some 

 amusement at being made a Doctor of Laws. " It 

 were better they made me Doctor of Science," he re- 

 marked. It was, however, pointed nut that as an 

 authority on the laws of thermodvnaniics the title was 

 a fitting one. 



In_ 1895 Boltzmann was transferred from Munich 

 to Vienna, where he resided until his death, with one 

 exception. In 1904 he was called to the University 

 of Leipzig, and actually went there for a short time, 

 but the change did not suit him, and he was back 

 again in Vienna almost immediately. 



In 1899 he was elected corresponding fellow of our 

 Royal Society, and allusion has alreadv been made to 

 the universal and widespread enthusiasm shown over 

 his diamond jubilee five vears later. 



Those who knew Boitzmann will rem"mber the 

 pair of heavy, highly-powerful spectacles resting on a 

 deep groove in his nose. For manv years his eye- 

 sight had been failing, and he found It increasingly 

 difficult to complete the manv researches which were 

 on his mind. He appears to have ended his life during 

 a summer holiday at or near Abbazia, a neighbour- 

 hood which he frequently visited with his wife and 

 family. 



We have alluded to some of Boltzmann 's earlier 

 writings more or less in chronological order. One 

 of his most important later works is his book 

 " Vorlesungen uber Gastheorie " (Leipzig : Barth), 

 the first volume of which bears the date 189:; and the 

 second 189S. It fills an important gap in the litera- 

 ture of the kinetic theory, and renders much of Boltz- 

 mann's own work more accessible to general readers 

 than it would be if his separate papers had to be con- 

 sulted. While Boltzmann 's chief energies were con- 

 centrated on the difficult problems of the kinetic 

 theory, other branches of physics were by no means 

 neglected. In evidence we have his book of lectures 

 on Maxwell's theory, papers on Hertz's experiments, 

 and an address on the methods of theoretical physics. 

 Artificial flight also interested the Vienna physicist, 

 who some years back gave a discourse on the subject, 

 illustrated by models. Among his recreations allusion 

 may be made to music. His thick fingers descending 

 on the keys of the piano well knew how to produce 

 those variations in timbre which are understood in 

 Germany, but the want of which makes English 

 people often say that the piano is devoid of soul. He 

 would often play in trios with his son and eldest 

 daughter. 



It may be that the kinetic theory of gases is even 

 now regarded as being less complete and perfect in 

 itself than many other physical theories, such as th° 

 electromagnetic theory of light. But the study of 

 irreversible phenomena stands on a far higher order 

 of difficulty than that of purely reversible effects. If 

 it has been impossible to build up a statistically irre- 

 versible system out of reversible elements without 

 NO. 1927, VOL 74"" 



making some assumptions, we are, at all events, in 

 possession of theories of molecular phenomena in 

 which the assumption in question is of the simplest 

 and most self-evident character, and the agreement 

 with experiment as close as could be expected. These 

 theories are in a very large measure results of the 

 labours of Ludwig Boltzmann. 



G. H. Brvan. 



NOT£5. 



Tme results of the Gordon-Bennett balloon race, as 

 announced in the daily papers, show that the sixteen 

 competitors who started from Paris on Sunday afternoon 

 all landed within a belt comprised between the meridians 

 of 1° east and 1° west of Greenwich. The longest and 

 most northerly journeys were those of Lieut. Lahm 

 (U.S..^.), who landed near Whitby — about 400 miles from 

 Paris — after a journey of 235 hours ; Signer Vonwiller 

 (Italy), near Hull ; Comte de la Vaulx (France), near 

 Walsingham, four miles from the Norfolk coast ; and the 

 Hon. C. S. Rolls, near Sandringham. A second group 

 landed in the south of England, this group comprising 

 M. J. Balsan (France), at Singleton, near Chichester; 

 Prof. Huntington (Great Britain), at Sittlngbourne, Kent ; 

 and Captain Kindelan (Spain), near Chichester. The next 

 group were carried from Paris in directions between west 

 and north-west, and landed on or near a strip of the French 

 coast extending from Dieppe to near Caen. These were 

 Herr Scherle (Germany), near Dieppe; Mr. F. H. Butler 

 (England), Comte de Castillon (France), and Senor 

 Salamanca (Spain), all three at Blonville, near Trouville ; 

 Baron von Hewald (Germany), at Coud^, near the mouth 

 of the Seine ; Captain von Abercron (Germany), at Villers- 

 sur-Mer ; and Lieut. Herrera (Spain), at Cabourg. A little 

 south of this group, M. Santos Dumont landed at Broglie, 

 after having met with an accident to his arm. A different 

 course was followed by the Belgian competitor, M. van den 

 Driesche, who landed at Bretigny, a place 19J miles south 

 of Paris, soon after midnight. 



Simultaneously with this competition, another of the 

 same character, in which seven balloons took part, started 

 from Milan. This was one of a number of aeronautical 

 competitions organised during the month of September in 

 connection with the exhibitions, other contests being 

 arranged for aeroplanes, machines, and models, both with 

 and without motive power. Whether owing to this clash- 

 ing or to other causes, the aeronautical pavilion at the 

 Milan Exhibition shows a remarkable dearth of exhibits, 

 the only really successful attempt at a complete and well- 

 organised exhibit being that of the Prussian Aeronautical 

 Observatory in Lindenburg. These exhibits mostly illus- 

 trated apparatus for the meteorological study of the upper 

 layers of the atmosphere, and their systematic display 

 under the charge of Prussian officials in their smart 

 military uniforms only made the absence of other important 

 e.xhibits the more conspicuous. 



The second International Conference on \A'ireless Tele- 

 graphy, which is now sitting in Berlin, is likely to prove 

 of great interest and importance from both the national 

 and commercial points of view. Delegates from nearly all 

 countries have accepted the German Government's invita- 

 tion, and are now in Berlin. The preliminary conference 

 of 1903, which was also convoked by the German Govern- 

 ment with the hope of securing general support for its 

 contention — that intercommunication between ships fitted 



