1902.] accompanying Mechanical Disturbance in Metals. 283 



Pig. 5. — Successive modifications of the "straight wire" ending in " cell form." 

 (b) shows how the ends of A and B of the wire may be vibrated by ebonite 

 clip-holders, H and H'. When A is excited, current of response in the wire, 

 normally speaking, is from the unexcited B to the excited A. The stimulated 

 wire becomes zincoid. Note that though the current of response is constant in 

 direction, the galvanometer deflection in (d) will be opposite in direction to {b) . 

 In (e) is shown one of the two graduated chcles by which the amplitude of 

 vibration is measured. 



the internal resistance of the cell and the variation of that resistance 

 by the addition of chemical reagents being thereby rendered quite 

 negligible. Ordinarily I use tap-water as the electrolyte. The 

 responses obtained with tap-water are practically the same as those 

 obtained with distilled water. Zinc wires in ZnS0 4 solution give 

 responses similar in character to those given by, for example, Pt or Sn 

 in water. 



Character and Intensity of Response dependent on Molecular Condition. 



The following experiments show how intimately the response 

 phenomena is connected with the molecular condition of the acted 

 wire : — 



Effect of Annealing. — The following photographic record, fig. 6, shows 

 the equal and opposite responses in A and B wires to a succession of 

 uniform stimuli. Hot water was now substituted for the cold water 

 (too high a temperature temporarily reduces the response) ; the cell 



