572 



NA TURE 



[April 12, 1900 



tious, but most zealous and enthusiastic worker. He died on 

 March 30, aged seventy-three. 



It was announced at the opening meeting of the Instilulion 

 of Naval Architects last week, that the council have accepted an 

 invitation from the president of the Association Technique 

 Maritime, M. L. de Bussy, to take part in the International 

 Congress of Naval Architects and Marine Engineers, which is 

 to be held in connection with the Paris International Exhibition. 

 To promote the success of this Congress, it has been determined 

 not to hold a separate summer meeting of the Institution this 

 year. An invitation has been received and accepted from the 

 Lord Provost, Magistrates, and council of Glasgow, to visit that 

 city in the year 1901. The council have awarded a gold medal 

 to Mr. J. Bruhn for his paper on " The Stresses at the Dis- 

 continuities in a Ship's Structure," and a premium to Prof. W. E. 

 Dalby for his paper, "The Balancing of Engines with special 

 Reference to Marine Work." In the course of his presidential 

 address, the Earl of Hopetoun referred to the necessity for 

 restricting the employment of wood in all fighting ships. Many 

 foreign nations are entirely abandoning the use of wooden decks 

 and wood fittings in their military marines. Among the sub- 

 jects of papers brought before the Institution were : — The action 

 of bilge keels, by Prof. G. H. Bryan, F. R.S. ; changes and 

 developments in the construction of ships for the mercantile 

 marine during the last forty years, by Mr. B. Martell ; dis- 

 tribution of pressure due to flow round submerged surlaces, 

 by Prof. Hele-Shaw, F. R.S. ; strength of elliptic sections 

 under fluid pressure, by Captain W. Hovgaard ; mysterious 

 fractures of steel shafts, by Signer R. Schanzer ; experi- 

 mental method of ascertaining the rolling of ships on waves, 

 by Captain G. Russo ; influence of depth of water on the 

 resistance of ships, by Major G. Rota ; and the balancing of 

 steam engines, by Herr Otto Schlick. 



An interesting illustrated article upon the construction of the 

 electric railway to the summit of the Jungfrau, and the electric 

 locomotives in use upon the completed sections, appears in the 

 Engineering Magazine (April). ^The total expense of boring 

 the tunnel, which will be ten kilometres long when completed, 

 is expected to be 200,000/. The method of boring is to pierce 

 a series of holes about a metre deep with two electric drills, and 

 then to explode cartridges in them. As the blasting operations 

 can only take place about four times a day, the daily progress is 

 comparatively small — only four metres. The debris passes into 

 tipping waggons worked by an endless rope, and is emptied out 

 at the nearest cross tunnel. At the entrance to the gallery there 

 is a temporary building containing two three-phase 200-kilowatt 

 transformers, reducing pressure from 7000 to 500 volts. The 

 three-phase, low-tension currents thus obtained are used for 

 driving the electric drills, working a ventilator to clear out the 

 smoke after an explosion, and providing power to melt snow for 

 the drills. When the tunnel reaches a height of above 3000 

 metres, it is expected that difficulties will be encountered on 

 account of mountain sickness. At present the majority of the 

 workmen employed are Italians, but above 3000 metres it is 

 almost certain that they will have to be replaced by Swiss 

 mountaineers. The last station of the railway will be about 

 66 metres below the summit, which is 4166 metres above sea- 

 level, and the journey from it to the summit will be accomplished 

 by means of a lift. A permanent meteorological observatory wil 

 be erected on the summit, the Pv.ailway Commission providing 

 100,000 francs towards its establishment, and 6000 francs 

 annually towards its maintenance. 



A PRELIMINARY report on the determination of the mass of 

 a cubic decimetre of water is published to the Proces verbaux of 

 the French International Committee of Weights and Measures, 

 by Dr. C. E. Guillaume. The method adopted was essentially 

 the same as those used in previous determinations, consisting in 



NO. 1 589, VOL. 6(] 



the observation of the weight of water displaced by a body 

 the dimensions of which were carefully measured. Dr. Guillaume 

 employed cylindrical forms, and from the mean of observations, 

 made with five cylinders of varying dimensions, the specific 

 mass of water at 4° was found to be 0*999936. 



Some observations on the influence of heating on the passage 

 of electricity through rarefied gases are contributed to Wiede- 

 mann's Annalen by Herr J. Stark. When the space between 

 the electrodes is just sufficient to prevent a discharge from taking 

 place, the introduction of an incandescent body causes the dis- 

 charge owing to the resistance of the gas decreasing on its being 

 heated. Similarly the fall of resistance caused by the use of an 

 incandescent kathode enables a comparatively small electro- 

 motive force to produce a luminous discharge. Herr Stark has 

 passed on to consider the case where the electromotive force is 

 about 100 volts, higher than that which would just suffice for 

 the discharge. In this case it is found that by the introduction 

 of a white-hot body all luminosity may be made to cease, the 

 electric discharge being dark. This effect the author attributes 

 to the heated gas having lost its power of phospherence during 

 the passage of electricity, a transformation which, moreover, is to 

 be accounted for by the gas becoming dissociated by the action 

 of heat, coupled with the property that no phosphorescence 

 occurs in a dissociated gas. 



A REINVESTIGATION of the question as to whether the 

 visc.isity of dielectric liquids is affected by a uniform electro- 

 static field is given by Dr. G. Pacher and Dr. L. Finazzi in the 

 Atti del R. Istituto Veneto, lix. 2. Contrary to the results 

 of Duff and Quincke, no variations in the viscosity were ob- 

 served to be caused by the electric field. The method of 

 experimenting was to measure the time of effiux through a pair 

 of liquid condensers, and the liquids operated on were distilled 

 water, ethyl-alcohol, ether, benzol, oil of turpentine and 

 sulphide of carbon. The times of efflux vary slightly in 

 individual experiments, owing to errors of observation ; but 

 there is no difference be tween the means of the results for 

 charged and uncharged condensers beyond what is naturally 

 attributable to accidental causes. 



The chief theorem of Lie's theory of continuous groups re- 

 ceives discussion at the h ands of Mr. Stephen Elmer Slocum in 

 the pages of the Proceedings of the x\merican Academy of Arts and 

 Sciences. The theorem in question is that a particular system of 

 r independent infinitesimal transformations generates a con- 

 tinuous group with r parameters, that is, a group with 

 r parameters in which each transformation can be gener- 

 ated by an infinitesimal transformation of the group. Prof. 

 Study, however, has shown that, notwithstanding the in- 

 finitesimal transformations of the special linear homogeneous 

 group satisfy Lie's criterion, nevertheless, not every trans- 

 formation can be generated by an infinitesimal transformation 

 of this group. Consequently Lie's theorem is subject to certain 

 limitations. So far as Mr. Slocum is aware, the precise nature 

 of the error has not been pointed out, and to show wherein it 

 consists is the object of his paper. The author carries out for a 

 particular group the successive steps in Lie's demonstration of 

 the first fundamental theorem of his theory, upon which the 

 chief theorem, namely the second fundamental theorem, rests. 

 At a certain point in this demonstration an assumption is made 

 in which Lie's error consists. 



In the Meteorologische Zeitschrift for January, Dr. H. 

 Hergesell continues his valuable discussion of the results of 

 recent international balloon ascents. In this paper he discusses 

 the effect of the density of the air upon the coefficient of 

 inertia of a ventilated thermometer. With respett to the 

 ascents of unmanned balloons, he finds that the registering 

 thermometers, although they may be properly protected against 

 solir radiation, only give accurate results during the ascent, 



