Discharge in Hare fled Gases. 187 



its rays ; and inasmuch as the coils embrace parts of the rays 

 lying nearer and nearer the point of origin of the rays, the 

 whole length of the rays becomes ultimately compressed into 

 a single magnetic curve. 



In exactly the same way the positive layers, which indeed 

 represent bundles of secondary negative light issuing from a 

 tube into one less by an indefinitely small amount, unroll them- 

 themselves from their ends turned towards the anode to the 

 point which, in the view we have taken, is to be regarded as 

 their point of origin— that is to say, the boundary of the layer 

 turned towards the negative pole. 



This boundary need not always preserve the same fixed 

 position under varied experimental conditions. Nevertheless 

 the rays always unroll themselves towards the place which 

 happens to be their point of origin. 



The appearance is very characteristic when the kathode- 

 light in the unmagnetized condition penetrates beyond the 

 first layer deep into the positive light. The end of the kathode- 

 light lies then further from the kathode than the end of the 

 first (and, according to the rarefaction, of the second, and so 

 on) positive layer. Nevertheless the end of the kathode-light 

 rolls itself up to the kathode into the magnetic curve which 

 passes through it, and separated from it by a dark space ; then 

 follows on the side of the anode a curve in which are combined 

 all the rays of the first positive layer, then a curve of the 

 second, and so on. 



This shows that it is not the absolute position and expansion 

 of the rays which determines the position they take when mag- 

 netized, but the intimate relationship which exists between all 

 the points of a ray and its point of origin, in consequence of 

 which each luminous body springing from a given point appears 

 as a single coherent whole, 



According to this representation the consecutive layers of a 

 • discharge do not follow on into each other, even when, in 

 consequence of the lengthening of their rays, each borders 

 closely on the next or even partially covers it. When, then, 

 each separate layer becomes combined into a single curve, 

 these curves must in general bo distinct, and not run together 

 into a connected surface of light, as would be the case if there 

 were a continuous current from each into the next. 



In fact we observe that when the magnet has combined the 

 layers into magnetic curves, the curves appear separated, 

 there being a dark space between each curve and the following- 

 one. 



Only when the exhaustion is so great, and the space in which 

 the discharge takes place so narrow, that the light disappears 



