On the Induction Apparatus and its Effects. 199 



of the objections that may be urged in reference to the fish being 

 provided with a special apparatus. In our first endeavours also 

 to obtain some result with the galvanometer, and in which we 

 failed to obtain any evidence of the existence of a force being 

 evolved, we were then led to the conclusion as to the improba- 

 bility of any force becoming free, as it were, during muscular 

 contraction ; that whatever force might be present would be 

 expended or converted during the act of contraction; but we 

 could never get over the difficulty which the results of Matteucci, 

 obtained by means of the frog, presented for our consideration, 

 and which is doubly increased by the results we have now related 

 in the present paper. In reference to the fish, also, we must 

 remember that the force evolved bears some relation, according 

 to Matteucci*, "to the activity of the functions of circulation 

 and of respiration, and of every act of nutrition." The appa- 

 ratus may be a means for the evolution of the force, but not a 

 producer of the force ; and we have some reasons for believing 

 that the electric condition of the blood in the living animal must 

 not be overlooked. 



We have pm"posely avoided referring in this discussion to the 

 influence and relations which the nervous system must bear to 

 muscular contraction ; and as it is our wish that these researches 

 should be considered as strictly experimental, whatever remarks we 

 might wish to make must be deferred to a future opportunity, 

 until circumstances will enable us to pursue the inquiry, and 

 with greater advantages than we now possess. 



XXIII. On the Induction Apparatus and its Effects. 



Btj J. C. POGGENDORFF. 

 [Concluded from p. 137.] 

 Appendix I. 

 On the Thermal Effect of the Induction Sparks. 



IN the foregoing memoir t, it was incidentally remarked that 

 a greater thermic action evidently exists in the stream of 

 sparks at the place of interruption of the induction wire, than 

 in that wire itself. This assertion is based not only upon the 

 facts there recorded, but also upon the prevalent opinion that 

 electric sparks always contain incandescent material particles, in 

 fact that they cannot otherwise be conceived to exist; an opinion 

 which many phsenomena I have observed appear to corroborate. 

 Nevertheless it may appear desirable to produce a direct proof 



♦ Phil. Trans. 1847, p. 241. 

 t Phil. Mag. vol. x. p. 122. 



