246 



similarly treated exhibited repulsion on making contact. It is 

 evident from these uniform results that the direction of flow obtained 

 by immersing the positive wire in the electrolyte and the negative 

 one in the mercury is almost uniformly positive. 



32. The movements obtained by this method are not produced by 

 the act of deposited substances dissolving in the mercury, for they 

 occur equally well whether hydrogen gas is set free and escapes or 

 alkali-metal is deposited and dissolves in the mercury, until in the 

 latter case the diminished mobility of the globule interferes with the 

 result. 



33. Considerable difficulty was experienced in examining liquids 

 by the second method, in consequence of the rapid and in many cases 

 instantaneous oxidation or filming of the metallic globule ; but by 

 using very dilute liquids and immersing the negative wire from 

 seventy-two small Smee's elements during only a moment at a time, 

 this difficulty was in most cases sufficiently overcome to allow di- 

 stinct starts of the mercury to occur in the particular direction 

 beneath its film, and thus to indicate an opposite motion of the 

 supernatant liquid, although in nearly all cases the movement of the 

 electrolyte itself could not be detected. Upwards of 100 liquids, 

 consisting of organic and inorganic compounds acid, alkaline, and 

 neutral were examined, and in more than three-fourths of them di- 

 stinct movements of the metal were obtained, which were in every 

 instance in a positive direction, thus indicating a negative flow of 

 the electrolyte. In some liquids, viz. oil of vitriol, moderately di- 

 lute nitric acid, strong solutions of sulphate of ammonia, iodide of 

 ammonium, and sulphite of potash, very dilute solutions of bisul- 

 phate of potash, iodide of potassium, nitrate of cobalt, hydro- 

 cyanic acid, cyanide of potassium, and acetic acid, visible move- 

 ments of the liquid itself in a negative direction were also ob- 

 tained. The movements of the liquid and of the metal very quickly 

 ceased. These experiments show that the direction of flow ob- 

 tained by placing the positive wire in the metal and the negative 

 wire in the electrolyte is always negative. 



34. The movements obtained both by methods 1 and 2 appear to 

 be produced by a mutual attraction of the liquid and metal ; in the 

 former case the mercury attracts an electro-positive element of the 

 liquid (hydrogen or an alkali-metal), and produces a positive flow ; 



