76 



NA TURE 



[May 26, 1904 



the mass of the same particle for slow speed ; calcula- 

 tion makes it 3.1 times. When the speed is 2.59 x io'°, 

 the observed mass ratio is 2-04; calculation makes it 

 2.0. When the speed is 2.36x10'°, observation gives 

 the ratio 1-65, calculation 1-5, which is not quite so 

 good an agreement ; but even this is nearer than any- 

 one could have anticipated, while the other results are 

 extraordinarily close. If Kaufmann's results stand the 

 test of criticism and repetition, they constitute a 

 verification of a fact which is of the utmost importance 

 and of the highest theoretical interest, for it has the 

 effect of reducing the whole Matter in the universe 

 to Electricity, not as a speculation, but as an estab- 

 lished truth. It would be rash to jump to such an 

 important conclusion too hastily ; and there remains 

 a great outstanding difficulty, hardly yet even faced, 

 concerning the nature of positive electricity — that vague 

 and cometary termination of lines which at the other 

 end are intensely concentrated. 



Moreover, the view taken by J. J. Thomson of 

 the nature of the lines of force — whereby their momen- 

 tum when moving depends upoa the mass of ether 

 vortically included in each and inseparable from 

 it— cannot be said exactly to explain "mass." 

 Material mass is first explained electrically, and then 

 electrical mass is relegated to the inertia of ether, — 

 not the great bulk of ether, which may be as regards 

 locomotion immovable, but the core of the columnar 

 vortices associated with and essentially constituting 

 the particles of which atoms of matter are composed. 

 The massiveness of ether itself would thus be an un- 

 explained fundamental fact, and its density would have 

 to be regarded as extremely great. The probably high 

 density of ether had already been surmised by 

 FitzGerald and others, and although by this means the 

 cosmos is reduced to a kind of glorified hydro- 

 dynamics, yet the fundamental properties of the con- 

 tinuous fluid itself remain unexplained and to all 

 appearance inexplicable. 



This may be regarded as a defect, but, after all, 

 explanation always proceeds by stages, reducing the 

 complex to the simple and introducing unification ; it 

 can hardly be considered likely that any theory 

 accessible to us here and now can give anything 

 approaching an ullimate explanation even of the 

 simplest thing. If the present theory can be sub- 

 stantiated, with whatever modifications and enlarge- 

 ments may be found to be necessary, it will be an 

 immense step in advance ; but it would be premature 

 to suppose that these views are in any sense final, or 

 that they will be promptly and universally accepted. 

 They have been led up to by the progress of science 

 during the last quarter century, and a welcome has 

 been gradually prepared for some of them, but the 

 discrete and real physical nature of the lines of force 

 radiating from an electric charge seems to me a 

 novelty ; although, as said before, a fibrous vortex 

 structure for the ether had already been suggested 

 and shown to be competent to transmit transverse 

 vibrations. This essential requirement for any ether, 

 the transmission of transverse vibration, necessarily 

 involves some " structure " in the ether, as Lord 

 Kelvin and others have all along perceived. Lord 



NO. 1804, VOL. 70] 



Kelvin favoured at one time a laminar structure, 

 FitzGerald a fibrous structure, and Hicks had his own 

 conception of a vortex sponge. But the difficulty in 

 most cases was to show that these arrangements were 

 stable and could persist without mutual destruction 

 or hopeless wire-drawing. It is not clear whether 

 this difficulty has or has not yet been attacked by 

 J. J. Thomson in connection with the pictorial re- 

 presentation which he now brings forward. 



He shows clearly, somewhat on the same lines as 

 Mr. Heaviside, how sudden jerks or accelerations given 

 to the lines must result in radiation, and he makes 

 many interesting thumb-nail calculations in connection 

 with their behaviour, among other things showing that 

 the mass of bound or associated ether in an electro- 

 static line is such that if moving with the speed of 

 light it would exactly equal the electrostatic energy of 

 the field per unit volume ; though how an electric field 

 is to be thus thought of in any static manner is not 

 clear to me. Also he is able to regard the re-distribu- 

 tion of the lines of a charge in rapid motion (first 

 calculated by Mr. Heaviside in the Phil. Mag., April, 

 1S89) as not only analogous to, but as really corre- 

 sponding to, the tendency of a moving cylinder to 

 set itself broadways to the direction of motion. 

 Furthermore, the lines of force behave very exactly as 

 stretched elastic threads ; for though their section is 

 not uniform, their tension, i.e. their total stretching 

 force, varies everywhere with their mass per unit 

 length, so that the rate of propagation of waves along 

 them is constant. 



Altogether a fascinating and most readable book for 

 students of physics and chemistry. 



Olixer Lodge. 



SIR A. GEIKIE'S RECOLLECTIONS. 

 Scottish Reminiscences. By Sir Archibald Geikie. 

 Pp. xii + 447. (Glasgow : Maclehose and Sons, 

 1904.) Price 6s. net. 



SCIENTIFIC readers will perhaps turn with most 

 interest to the chapter in this charming book in 

 which Sir Archibald, the last Scotchman for the time 

 being who has directed the work of the Geological 

 Survey of Great Britain, tells the story of the Scottish 

 School of Geology. It is interesting to read along 

 with it the pathetic lament of Principal Forbes, in 

 Edinburgh, in 1862. 



" It is a fact which admits of no doubt that the 

 Scottish Geological School which once made Edin- 

 burgh famous, especially when the Vulcanist and 

 Neptunian war raged simultaneously in the hall of 

 this society " — the Royal Society of Edinburgh — " and 

 in the class rooms of the LIniversity, may almost be 

 said to have been transported bodily to Burlington 

 House. Roderick Murchison, Charles Lyell, Leonard 

 Horner, are Scottish names, and the bearers of them 

 are Scottish in everything save residence — our younger 

 men are drafted off as soon as their acquirements 

 become known. Of all the changes which have be- 

 fallen Scottish science during the last half century, 

 that which I most deeply deplore, and at the same 

 time wonder at, is the progressive decay of our once 

 illustrious Geological School. Centralisation may 

 account for it in part but not entirely." 



