92 



Dr. G. Gore. 



4. Relation to Immiscibility of the Liquids. 



Is it a necessary condition of the movements that the two liquids 

 must be incapable of mixing with each other ? In the year 1859 

 (see " Proc. Roy. Soc," vol. 10, p. 235, par. 9) I made some ex- 

 periments bearing upon this question : " 1st, a definite layer of oil 

 of vitriol was placed beneath a layer of distilled water weakly acidu- 

 lated with sulphuric acid, and the terminal wires (from a voltaic 

 battery) immersed in the upper liquid; no visible movements 

 occurred at the boundary line of the two liquids ; 2nd, a dense solution 

 of cyanide of potassium was placed in a small glass beaker, a few 

 particles of charcoal were sifted upon its surface, and a layer of 

 aqueous ammonia half an inch deep carefully poured upon it. A 

 vertical diaphragm of thin sheet gutta-percha was then fixed so as 

 completely to divide the upper liquid into two equal parts ; the vessel 

 was placed in a strong light, and two horizontal platinum wire 

 electrodes from sixty-six pairs of freshly charged Smie's cells im- 

 mersed one-eighth of an inch deep in the liquid ammonia on each 

 side of the diaphragm. A copious current of electricity circulated, 

 but no movements of the liquids at their mutual boundary line could 

 be detected. A small globule of mercury placed in the lower liquid 

 at once produced evident signs of motion." 



Fig. 1. 



