ELECTRICITY IN RELATION TO SCIENCE. 499 



even lighted a room by producing in it sucli a condition that an 

 illuminating appliance may be placed anywhere and lighted with- 

 out being electrically connected with anything. He has produced 

 the required condition by creating in the room a powerful elec- 

 trostatic field alternating very rapidly. He suspends two sheets 

 of metal, each connected with one of the terminals of the coil. If 

 an exhausted tube is carried anywhere between these sheets, or 

 placed anywhere, it remains always luminous. 



The extent to which this method of illumination may be prac- 

 tically available experiments alone can decide. In any case, our 

 insight into the possibilities of static electricity has been extended, 

 and the ordinary electric machine will cease to be regarded as a 

 mere toy. 



Alternating currents have at the best a rather doubtful repu- 

 tation. But it follows from Tesla's researches that as the rapidity 

 of the alternation increases they become not more dangerous but 

 less so. It further appears that a true flame can now be produced 

 without chemical aid — a flame which yields light and heat with- 

 out the consumption of material and without any chemical pro- 

 cess. To this end we require improved methods for producing 

 excessively frequent alternations and enormous potentials. Shall 

 we be able to obtain these by tapping the ether ? If so, we may 

 view the prospective exhaustion of our coal-fields with indiffer- 

 ence ; we shall at once solve the smoke question, and thus dissolve 

 all possible coal rings. 



Electricity seems destined to annex the whole field, not merely 

 of optics, but probably also of thermotics. 



Rays of light will not pass through a wall, nor, as we know 

 only too well, through a dense fog. But electrical rays of a foot 

 or two wave-length of which we have spoken will easily pierce 

 such mediums, which for them will be transparent. 



Another tempting field for research, scarcely yet attacked by 

 pioneers, awaits exploration. I allude to the mutual action of 

 electricity and life. No sound man of science indorses the asser- 

 tion that " electricity is life " ; nor can we even venture to speak 

 of life as one of the varieties or manifestations of energy. Never- 

 theless, electricity has an important influence upon vital phe- 

 nomena, and is in turn set in action by the living being — animal 

 or vegetable. We have electric fishes — one of them the prototype 

 of the torpedo of modern warfare. There is the electric slug 

 which used to be met with in gardens and roads about Hornsey 

 Rise ; there is also an electric centiped. In the study of such 

 facts and such relations the scientific electrician has before him 

 an almost infinite field of inquiry. 



The slower vibrations to which I have referred reveal the be- 

 wildering possibility of telegraphy without wires, posts, cables, or 



