386 On the Electric Discharge in Rarefied Gases. 



the apparatus is constructed), x lies between the kathode K and 

 y. If the kathode K is movable, we observe first that its motions 

 only affect the stratifications between it and x, but, on the other 

 hand, all between x and y, as well as those between y and A, 

 are unaffected. If x is moved, we find that the motion of this 

 pole causes a motion only of the stratifications between x and 

 y ; the stratifications between y and A remain unmoved. In 

 the same way, when the magnitude of the negative pole varies, 

 it is found that only changes in the pole y affect the position 

 of the stratifications between y and A. 



Hence the position of each stratification depends on the 

 position and properties of the secondary negative pole, or 

 pencil of secondary negative light nearest to it. But since 

 each separate positive layer, even in a simple cylinder, is, as I 

 have sho wn*, only a form of the secondary negative pencil (the 

 section of its origin is itself a secondary negative pole), it fol- 

 lows that the position and properties of each separate layer, 

 even in a simple cylinder, do not depend so much upon the 

 kathode and kathode-light as upon the position and properties 

 of the layer immediately near it. If, then, in a simple cylinder 

 all the stratifications are put into motion by displacing the 

 kathode, it follows that the motion of the kathode itself properly 

 causes only a corresponding change in the position of the 

 kathode-light which issues from it ; the displacement of the 

 point of origin of this last displaces the surface of origin of 

 the first positive layer ; this change displaces the surface of 

 tension for the second layer, and so on. 



I have mentioned that, in a simple cylinder, the consecutive 

 intervals between the stratified layers of the positive light 

 differ very little from each other ; but if we observe also the 

 very small differences which present themselves, we find that 

 the intervals gradually decrease from the kathode towards the 

 anode. If the space in which the discharge takes place be 

 contracted at any point whatever so as to produce a secondary 

 negative pole, then the intervals diminish only up to this pole; 

 beyond it the intervals suddenly increase and a new series of 

 decreasing intervals begins, again increasing beyond a new 

 secondary pole, and so on. We find, then, that the magni- 

 tude of each stratification-interval is determined by the ratio 

 of the secondary negative pencil produced by the change of 

 section which immediately precedes the interval under consi- 

 deration. 



In passing to infinitely small changes in section when the 

 secondary negative pencil passes into a positive layer, we find 

 that the magnitude of the interval between any two layers 

 * Goldstein, Berl Mu»atsber. 1876, p. 280 : Phil. Mag. [5] iv. v . 36L 



