SS2 Dr. W. H. Eccles on Coherers, 



Since p = p {l — u6), (1) becomes 



kp oc . pc 2 + mp = mp . . 



dp 



dt "• 



ao 



The simultaneous equations (1/) and (2) contain the 

 complete history of the fluctuations of c and p from any 

 assigned equilibrium condition. We need only investi- 

 gate here small fluctuations. First, however, let us obtain 

 the equilibrium value of e, say c 1} corresponding to a 

 given value of the applied electromotive force e. Put 

 dc/dt = and dp/dt = in (]/) and (2) and eliminate p. 

 get 



/ _^ \ 



\m -f- kocp c J 



We 



(3) 



This equation agrees perfectly with the results of numerous 

 experiments on the iron-oxide-iron coherer. For example, 

 the experimental curve of fig. 7 has the parameters 



r = 390 ohms, p = 970 ohms, 



ka 



3-7 xlO 6 . 



Fig. 7. 



0-2 0-4 0-6 0-8 



Iron point on oxidized iron plate. Steady current curve. 



In general it would appear that the curves drawn from 

 experiments on detectors should fall into the two classes 



