ADDRESS BEFORE THE AMERICAN INSTITUTE OF ELECTRICAL ENGINEERS, 

 NEW YORK, MAY 22, 1889 



[Transactions of the American Institute of Electrical Engineers, VI, 342-357, 1889] 



As, a short time since, I stood in a library of scientific books and 

 glanced around me at the works of the great masters in physics, my mind 

 wandered back to the time when the apparatus for a complete course 

 of lectures on the subject of electricity consisted of a piece of amber 

 and a few light bodies to be attracted by it. From that time until 

 now, when we stand in a magnificent laboratory with elaborate and 

 costly apparatus in great part devoted to its study, how greatly has the 

 world changed and how our science of electricity has expanded both in 

 theory and practice until, in the one case, it threatens to include within 

 itself nearly the whole of physics, and in the other to make this the age 

 of electricity. 



Were I to trace the history of the views of physicists with respect 

 to electric currents it would include the whole history of electricity. 

 The date when the conception of an electric current was possible was 

 when Stephen Gray, about 170 years ago, first divided bodies into con- 

 ductors and non-conductors, and showed that the first possessed the 

 property of transmitting electrical attractions to a distance. But it 

 was only when the Leyden jar was discovered that the idea of a current 

 became very definite. The notion that electricity was a subtle fluid 

 which could flow along metal wires as water flows along a tube, was 

 then prevalent, and, indeed, remains in force to-day among all ex- 

 cept the leaders in scientific thought. It is not my intention to depre- 

 ciate this notion, which has served and still serves a very important pur- 

 pose in science. But, for many years, it has been recognized that it in- 

 cludes only a very small portion of the truth and that the mechanism by 

 which energy is transmitted from one point of space to another by means 

 of an electric current is a very complicated one. 



Here for instance, on the table before me are two rubber tubes filled 

 with water, in one of which the water is in motion, in the other at rest. 

 It is impossible, by any means now known to us, to find out, without 

 moving the tubes, which one has the current of water flowing in it and 



