366 C. A. Peters — Electrolysis of Sodium Chloride 



Apparatus. 



Cell. — The cell used was the one described by Hildebrand* 

 consisting of a bottomless beaker Q''d cm in diameter and Q'3 im 

 tall set into a crystallizing dish 11 "3™' in diameter and 5 - 7 cm 

 high. Midway between the cells, above the mercury, was a 

 coil of 6 turns of nickel wire t'" m in diameter. At three 

 places on the nickel wire a single wire ran down forming legs, 

 in the feet of which rested the ends of a Y. This Y, made of 

 glass rod 3 mm in diameter, formed the support for the inner 

 cell and also held the nickel wire in position when the whole 

 apparatus was inverted in emptying. Three rubber stoppers 

 placed radially held the inner cell in position. The apparatus 

 is pictured by Hildebrandf and also in Smith's Electro- 

 Analysis. Less than 2 kg. of mercury sealed the two compart- 

 ments. The contact with the cathode was made through' an 

 S-shaped tube filled with mercury which hung on its side on 

 the edge of the outer cell. The S-shaped tube had a platinum 

 wire sealed in one end dipping under the cathode mercury. 



J^lated Anode. — The anode was the platinum one previously 

 used in this laboratory,^: consisting of two circular discs of 

 platinum gauze, 300 meshes to the sq. cm., attached l cm apart 

 to the end of a heavy platinum wire. The weight was about 

 16'5 grms. When plated the weight was increased to 21 or 

 22 grms. A loop of platinum wire was easily welded on the 

 stem (best extending above the top) by means of which the 

 anode was suspended in the balance or in the heating apparatus. 



Silver Anode. — Described later when used, p. 382. 



Electrical Apparatus. — The rotating apparatus was one 

 with which this laboratory is equipped, and operated by the 110 

 volt direct current circuit. The ammeter was of American 

 Instrument Company's make graduated to "01 of an ampere. 

 Storage batteries furnished the energy for electrolysis. 



Air Bath. — Some of the time the anode was dried in an 

 air bath. This consisted of two sheet iron cylinders each 

 about 20 inches high set one inside the other, the inner one 

 about 4 inches in diameter and single ; the outer one about 7 

 inches, double, and filled with asbestos. The lower end of 

 the inner cylinder was fitted with two iron covers packed with 

 asbestos to prevent the entrance of the gases from the Bunsen 

 burner. A tinned copper or iron cover placed over the inner 

 cylinder, through which passed a nickel wire holding the 

 anode, and a nasbestos cover over all, greatly increased the 

 heat. A thermometer through both covers gave the tempera- 

 ture, which could be regulated approximately anywhere up to 

 600°. 



*Jour. Amer. Chem. Soc, xxix, 451. 



fL. c. 



\ Gooch and Eead, this Journal, xxviii, 544, 1909. 



