34-2 Dr. Faraday's Experimental Researches in Electricity. 



trode, in sulphate of soda or solution of common salt, gave 

 the same constancy of operation. 



813. Experiments of a similar kind were then made with 

 bodies altogether in a different state, i. e. with fused chlorides, 

 iodides, &c. I have already described an experiment with 

 fused chloride of silver, in which the electrodes were of me- 

 tallic silver, the one rendered negative becoming increased 

 and lengthened by the addition of metal, whilst the other was 

 dissolved and eaten away by its abstraction. This experiment 

 was repeated, two weighed pieces of silver wire being used as 

 the electrodes, and a volta-electrometer included in the cir- 

 cuit. Great care was taken to withdraw the negative elec- 

 trode so regularly and steadily that the crystals of reduced 

 silver should not form a metallic communication beneath the 

 surface of the fused chloride. On concluding the experiment 

 the positive electrode was re-weighed, and its loss ascertained. 

 The mixture of chloride of silver, and metal, withdrawn in 

 successive portions at the negative electrode, was digested in 

 solution of ammonia, to remove the chloride, and the metallic 

 silver remaining also weighed : it was the reduction at the cat- 

 hode 9 and exactly equalled the solution at the anode; and each 

 portion was as nearly as possible the equivalent to the water 

 decomposed in the volta-electrometer. 



814. The infusible condition of the silver at the tempera- 

 ture used, and the length and ramifying character of its cry- 

 stals, render the above experiment difficult to perform, and 

 uncertain in its results. I therefore wrought with a chloride 

 of lead, using a green glass tube, formed as in fig. 17. A 

 weighed platina wire was fused into the bottom of a small 

 tube, as before described (789.). The tube was then bent to 

 an angle, at about half an inch distance from the closed end; 

 and the part between the angle and the extremity being soft- 

 ened, was forced upward, as in the figure, so as to form a 

 bridge, or rather separation, producing two little depressions 

 or basins a, b 9 within the tube. This arrangement was sus- 

 pended by a platina wire, as before, so that the heat of a 

 spirit-lamp could be applied to it, such inclination being given 

 to it as would allow all air to escape during the fusion of the 

 chloride of lead. A positive electrode was then provided, by 

 binding up the end of a platina wire into a knob, and fusing 

 about twenty grains of metallic lead on to it, in a small closed 

 tube of glass, which was afterwards broken away. Being so 

 furnished, the wire with its knob was weighed, and the weight 

 recorded. 



815. Chloride of lead was now introduced into the tube, 

 and carefully fused. The leaded electrode was also intro- 



