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phuric acid, but obtained no movements. 5th. No movements took 

 place with globules of chloroform in a solution of caustic potash or of 

 sulphate of alumina. 



9. To determine whether one of the substances must be metallic : 

 1st. A definite layer of oil of vitriol was placed beneath a layer of 

 distilled water weakly acidulated with sulphuric acid, and the terminal 

 wires immersed in the upper liquid ; no 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 

 j 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 66 pairs of 

 freshly- charged Smee's batteries immersed |-th 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. One 

 of the substances must therefore be a metallic conductor of electricity. 



10. To ascertain whether the capability of producing these move- 

 ments was a general property of metals and alloys when in the liquid 

 state : 1st. Bismuth was fused beneath a layer of chloride of zinc ; 

 tin was also melted under a similar layer, and the terminal wires im- 

 mersed in the supernatant liquid ; a steady negative flow occurred in 

 each case. 2nd. Cadmium was similarly treated under fused cyanide 

 of potassium, and a positive flow obtained. 3rd. Cadmium, lead, 

 Britannia- metal, and fusible metal were melted separately, small pieces 

 of cyanide of potassium placed upon them and melted, the metal con- 

 nected with the negative platinum wire, and the positive wire dipped 

 into the melted cyanide ; positive repulsions took place with each 

 metal on making contact. I conclude from these experiments that 

 the power of rotating under the influence of an electrolytic current is 

 a general property of metals and alloys when in a liquid state. 



1 1 . That the mass or body of the metal is not essential to the 

 production of the movements, is evident from the fact that the move- 

 ments have been readily obtained with thin layers of mercury upoa 

 amalgamated zinc (7) and copper plates. 



