Page:Collected Physical Papers.djvu/307

Rh movement of the galvanometer spot. At N$1$ there was no movement, but there was an upward movement of

response when the explorer came over the stimulated area "Carbonate." As the explorer passed on to N$2$ there was a cessation of movement, but when it reached the depressed area marked "Oxalic" there was a vigorous movement downwards (fig. 73).

I have already described a case of interference in the galvanometric effect when the two points A and B in similar molecular conditions are simultaneously acted on by the same mechanical stimulus. Under these