270 



particle to another within that extent of the series which is 

 already fully agitated. In other words, the communicated 

 vibration does not attain a sensible amplitude, until a finite 

 interval of time has elapsed from the moment when one 

 should expect it to begin, judging only by the law of the 

 propagation of phase through an indefinite series of particles, 

 which are all in vibration already. A small disturbance, dis- 

 tinct from the vibration (3)', is also propagated, backward as 

 well as forward, with a velocity = a, independent of the 

 length of the wave. And all these propagations are accom- 

 panied with a small degree of terminal diffusion, which, after 

 a very long time, renders all the displacements insensible, if 

 the number i, however large, be finite, that is, if the vibra- 

 tion be originally limited to any finite number of particles. 



Dr. Apjohn read a paper by George James Knox, Esq. 

 "on the Direction and Mode of Propagation of the electric 

 Force traversing Media which do not undergo Electrolyza- 

 tion." 



In the commencement of this paper, the author details 

 experiments, which appear to him to justify the inference, 

 that when an electric circuit is completed through water or 

 melted phosphorus, the current passes directly through the 

 substance of these media, but that when, for these, a metal 

 such as lead is substituted, the electricity moves exclusively 

 along its surface. He next considers the source and mode 

 of propagation of the electric force, developed in the pile, 

 and after a brief review of the theories and experiments of 

 Davy, Faraday, and Becquerel, arrives at the following con- 

 clusion, viz. that an electric current originates in a natural 

 electro-inductive power of bodies when brought into contact, 

 which affects the circumambient ether of each particle, and 

 is continued by alternate states of induction and equilibrium; 

 the amplitude of the oscillations of the electrical ether con- 



