192 



OF Mrsn.r.s AND NF.RVKS. 



dinal section, and <i rand J> >/ arc transverse 

 through tin- cross-section. The curved lines represent 

 the divert ing arches, and the arrows show the direction 

 of the currents which arc generated in these. No 

 currents are generated in arches 0, 7, or 8, for these 

 unite symmetrical points. 



Moreover, the rate at which the tension decreases 

 in the longitudinal section is, not regular, Imt at a 

 gradually increasing speed from the equator to the 

 en-Is. If, therefore, we find these iso-e!ectric curves, the 



l-'i<;. fill. Ci IIUKNTS IN A Mix u; ritis.M. 



tensions of which differ by a definite amount, these, in 

 the centre of the muscle-prism, are at some distance 

 from each other, but gradually approach more closely 

 together toward the edge of the cross-section. If the 

 ten-ion prevailing at each point in one side of a longi- 

 t ndiinl sec! ion is represent ed by the height of a >< raight 

 line drawn at right angles to that side of the longitu- 

 dinal section, then the ciirxe \\hieh unite.- the heads of 

 thc-e lines is level at the centre of < he longitudinal 

 sect ion, but sinks rapidly do\\n to\\ard 1 he edges of the 

 cross-.-ection. Asome\\hat similar fact is observable on 



