Electro-deposited Antimony. 445 



about 79° Fahr. ; on interposing a galvanometer, the conductivity 

 of the cii'cuit was found to be gi'adually increased during the 

 rise of temperature, and gradually decreased during the fall. 

 These phajnomena were repeatedly produced by reheating the 

 same portion of liquid ; and similar effects were obtained with 

 the solution composed of tartar-emetic and dilute hydrochloric 

 acid. The first liquid exhibited no material irregularity in its 

 rate of cooling, indicative of molecular change, between 220° 

 and 100° Fahr. By previously evaporating the same solution to 

 one-half its original bulk, its tendency to yield a gray deposit by 

 heat was considerably reduced ; and by diluting it either with 

 pyroxylic spirit, dilute hydrochloric acid, or solution of table- 

 salt, its aptitude to give gray metal at ordinary temperatures 

 was increased and its depositing quality injured. 



12. Upon examining the electric relations of the depositing 

 liquids with platinum plates in the apparatus described at page 

 1 of the Philosophical Magazine, January 1857, hot platinum 

 was found to be increasingly electro -negative to cold platinum 

 up to 210° Fahr. in the tartaric-acid solution, in accordance 

 with the general rule there stated ; but with the first liquid an 

 unusual variation occurred, hot platinum being increasingly 

 negative to cold platinum up to 110° Fahr., then decreasingly to 

 145° Fahr., and above that temperature increasingly positive to 

 210° Fahr. Similar effects wore obtained with small square co- 

 lumns of Duboscq's carbon (made by him for electric light appa- 

 ratus) immersed in those liquids in V-tubes. In each case the 

 solution was previously boiled, and repeated experiments gave 

 uniform results. 



13. By separating the first and second solutions from each 

 other by means of a porous diaphragm, and immersing two per- 

 fectly similar pieces, cither of platinum or of Duboscq's carbon, 

 one in each liquid, and connecting them with a galvanometer, 

 that in the chloride solution was in each case found to be rather 

 strongly electro-positive to that in the tartaric-acid liquid. 



14. In depositing from cither of the solutions which yield the 

 amorphous metal, especially ordinary chloride of antimony nearly 

 saturated with antimony by the battery process, there is a great 

 tendency in the deposit to extend itself in the form of a thin 

 sheet of gray metal upon the surface of the liquid : this lateral 

 sj)rcudof the metal is unique, and increases ra])idly j and, like the 

 gray excrescences formed upon other parts of an aniorjihous de- 

 posit, its speed of increase is mucli greater than that of the dark 

 metal near it (see 10) ; the reason of this appears to be that 

 crystalline antimony is more electro-negative than the amorphous 

 variety, and therefore receives the electric current witli greater 

 facility. I have found with perfect specimens of gray and dark 



