﻿220 M. W. von Bezold's Investigations on the Electrophones* 



tricity passes to the surface B in the form of sparks. But this 

 quantity of electricity is insufficient to overcome the action at a 

 distance of the negative electricity of A, and hence it will not be 

 recognizable by the electroscope. Indeed, on the average, as we 

 shall afterwards see, the action of the primarily excited negative 

 electricity will still somewhat predominate. Investigated by means 

 of the powder, the positive star is seen upon B — not, however, 

 yellow on a neutral ground, but black (that is, free from dust) on 

 a red ground, if the disk was dusted while held in the hand, or, 

 still better, laid upon high insulating supports. That is, the 

 action of the primary negative electricity prevents the nega- 

 tive sulphur from lying upon the places covered with positive 

 electricity ; and the presence of such places is only evidenced by 

 the smaller attraction which they exert towards the red lead. If 

 the action at a distance of the primarily excited electricity be 

 diminished by placing the disk with the rubbed side upon a 

 plate in connexion with the earth, yellow stars will appear im- 

 mediately after the dusting. 



The experiments with the flame may be explained in an en- 

 tirely analogous manner. If, for instance, the unrubbed side B 

 be passed through the flame, it is readily seen that on this side 

 positive electricity must be accumulated, even if it be assumed 

 that there was previously no electricity upon it, and that its elec- 

 troscopic indication was only occasioned by the action at a dis- 

 tance of the electricity primarily excited upon A. We may even 

 suppose that the decomposition by induction is transferred to the 

 flame itself, or to the layer of precipitated vapour which is every- 

 where formed on the plate when the flame is passed over it. But 

 in that case negative electricity must be removed by the action of 

 points of the flame, while the positive electricity remains upon 

 the surface. 



If now the surface A is treated with the flame, the negative 

 electricity present can only partially be removed, since it is mostly 

 bound (if I may be allowed the expression) by the positive of the 

 surface B. Of course the positive electricity now present upon 

 B preponderates ; and thus, as Biess states, by alternately passing 

 the surfaces through the flame, first one and then the other elec- 

 tricity will preponderate, of course with continually diminishing 

 intensity. Making the experiment with the mixed powder, if 

 first of all only a small place upon a plate of ebonite is rubbed, 

 we see red and yellow spots alternately formed upon the corre- 

 sponding sides. 



In order to explain the positive electricity which appears upon 

 B after it has been laid upon an earth- connected plate, or has been 

 once treated by the flame, Eiess assumes that there is a positive 

 layer in the interior. Hence, to explain the last-named fact, he 



