MUSCLES, NERVES, AND ELECTRICAL ORGANS. 183 



never possible to say if or when the restoration is complete. The 

 same thing occurs with negative polarisation. Polarisation curves, 

 however, drawn relatively to the opening time, present other 

 important peculiarities. If the opening occurs at the critical time 

 there often follow deflections in two opposite directions, corre- 

 sponding first to negative and then to positive polarisation. The 

 transition from purely positive polarisation to purely negative, 

 through such double action, may be explained in the manner expressed 

 by Fig. 6. It must not be imagined that from the opening of the 

 primary circuit to the change of sign of the polarisation, the action 

 is simply positive and then simply negative. It is much more 

 likely that both are present from the moment of closure, and 

 increase in accordance with a different law, by which the negative 

 polarisation increases more in proportion to the time of closure, 

 while the positive rises first quickly and then slowly. In the figure 

 this is represented on the vertical plane, which is seen in perspec- 

 tive stretching from left to right backwards. In this plane the 

 abscissal axis oTis the increasing time of closure, the broken curve 

 from o to + P is that of the positive polarisation for a given den- 

 sity of current, the dotted one from o to P that of the negative 

 polarisation for the same density drawn relatively to the time of 

 closure. If the ordinates of these component curves l are summed 

 up algebraically, and the result inscribed according to its positive 

 or negative value above or below the abscissal axis, you have the 

 resulting curve o (-\-m) T^ ( m), which at T k , the critical time of 

 closure, intersects the abscissal axis o T, and in fact is nothing but 

 one of the polarisation-curves drawn with reference to the time of 

 closure such as we had in Fig. 5. The negative maximum, with a 

 longer time of closure, is explained by the supposition that the 

 curve of negative polarisation either begins to sink, or rises more 

 slowly than the positive, or that the latter begins to rise more 

 quickly (Sect. IT and 21). 



On vertical planes which meet at a right angle the -tf-T-plane of the 

 polarisation-curves, drawn relatively to the time of closure, the com- 

 ponent polarisation-curves are represented relatively to the time of 

 opening ; the abscissal axes ^ z 19 t 2 z z , t 3 z s represent in each case the 

 increasing time of opening. The polarisation-curves drawn rela- 

 tively to the time of opening are treated in a corresponding way to 

 those of the time of closure, from which they proceed. The com- 

 ponent positive ones are shown by interrupted lines, the component 



1 Cf. Untersuchungen am Zitfceraal, p. 215. 



