MODERN SCIENCE. 259 



of molecules, reduced to a minimum in a glass bulb 

 by the air-pump, is focussed by means of electricity on 

 any point, and a piece of platinum is placed at that 

 point, its hammering is so mighty that the platinum be- 

 'comes white-hot in a few moments. Mr. Crookes believes 

 that he is on the track of a fourth condition of matter, 

 as distinct from the gaseous as the gaseous is from the 

 liquid condition, and the liquid from the solid ; and the 

 assumption does not seem unfounded. The certainty of 

 the existence of this tremendous force opens a field to 

 human possibilities the extent of which it is impossible to 

 exaggerate, as the following paragraph will show. Crookes 

 has already described, with that fertility of imagination 

 which distinguishes him, some of the multifarious and 

 beneficent applications which science may devise from the 

 knowledge he has imparted to us. Crookes, as we have 

 seen in our Chemical section, has carried on researches of 

 the very highest import in Chemistry. 



b. i863(?). Tesla (Nikola) constructed a dynamo which 

 gives 20,000 ALTERNATIONS per second instead of 100 ; and 

 by means of condensers he multiplied the alternations until 

 they exceeded 1,500,000 PER SECOND obtaining thereby 

 a current 15,000 times more powerful than hitherto.* Once 

 in possession of this undreamt-of engine, he launched into 

 a series of experiments the phenomena of which open a 

 new and mysterious region : (i.) Whereas a current of less 

 than 2,000 volts kills a man, a current of 50,000 as obtained 

 by Tesla gives no shock it cannot even be felt so that 

 the experimenter is able to play with flashes of lightning; 

 (II.) whereas our insulators effectually stop an ordinary 

 current, the Tesla current will shoot a stream of sparks 

 between two poles through such a safe insulator as vulcanite 

 just as it would through air; (ill.) whereas in Crookes' 

 radiant matter experiments the aid of 'wires is necessary, 

 the Tesla forces take effect at a considerable distance 

 through space, and "if metal plates are fixed on the roof 

 and walls of a room, and connected with the terminals, 



* Nineteenth Century Review. March, 1892, Number. J. E. H. 

 Gordon. 



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