48 



Chemico- Electric Relations of Metals. [Dec. 18,. 



5 and 120 ; Co and Sb in 320 and 400 ; Co and Tl in 360 and 400 ; 

 Co and Hg in 320, 360, and 500 ; Pt and Si in 10 ; and C and Rh in 

 the 5 grs. solution. 



Table No. IX. — In Fused Cyanide of Potassium. 



The following was the order obtained by immersing the various 

 elementary substances in cyanide of potassium in a fused state ; the 

 first substance being the most positive : magnesium, zinc, aluminium 

 and platinum, nickel, iron, silver, iridium, gold, rhodium, carbon, 

 palladium, cobalt, antimony. 



From the notes appended to the foregoing tables, it may be ob- 

 served — 1st, that by far the greatest number of momentary reversals 

 of current took place in the cyanide solutions, especially in the cold 

 ones ; 2nd, that the proportions of such reversals to the number of 

 solutions employed were not greatly different in the chloride, bromide, 

 and iodide of potassium ; and 3rd, the reversals were not confined to 

 the more electro-positive metals. The most numerous reversals in the 

 cold solutions of potassic cyanide took place with nickel (26), alumi- 

 nium (21), silver (18), platinum (16), magnesium (15), and zinc (14) - 

 and in the hot solutions, with aluminium (16), magnesium (14), and 

 zinc (11) ; whilst in the cold iodide solutions the most frequent ones 

 were nickel (7), iron (6), silicon (4), and cobalt (4) ; and in the hot 

 liquids, nickel (10), silicon (8), iron (7), and cobalt (8) ; most of these 

 occurred in the strong solutions. With the cold bromide mixtures 

 reversals occurred with aluminium (6), iron (5), gold (5), and palla- 

 dium (4) ; with the same liquids hot, indium (6), aluminium (5), 

 and iron (4). And with the chloride solutions cold, iron (3) ; and 

 hot, aluminium (3), and cadmium (3). The behaviour of particular 

 pairs of metals in different liquids with regard to reversals may be 

 ascertained by inspection of the notes. 



Certain other general effects were also observed in the results. 1st. 

 Gas carbon was electro-negative to all other bodies in all the solutions 

 employed, whether cold or hot ; concentrated or dilute. 2nd. Rho- 

 dium was electro -negative to all substances except carbon, in all solu- 

 tions of either iodide or cyanide of potassium, of all degrees of con- 

 centration, and at each temperature. 3rd. Either rhodium or platinum 

 was negative to all bodies except carbon in all the solutions of chloride 

 or bromide of potassium, whether cold or hot. 4th. Magnesium was 

 positive to all the other substances in all the solutions of potassic 

 chloride, bromide, or iodide, at each temperature. 5th. Either mag- 

 nesium, aluminium, or zinc, was positive to all other metals in solu - 

 tions of potassic cyanide, whether cold or hot. Thallium appeared 

 to be the most quickly corroded of any metal in all the solutions, and 

 was most manifestly affected in those of potassic iodide ; lead was also 

 acted upon, but to a less extent, in that class of liquids. 



