50 LETTEES OF BEKZELIUS 



bleached by electricity in the following manner. 

 The strip, in a moist condition, was placed on a 

 platinum plate which was in metallic contact with 

 the earth. A brass wire was fixed to the conductor 

 of the electrical machine so that its free end reached 

 to within a third of an inch of the strip. When the 

 electrical machine was set in motion, part of the strip 

 was thus in the electrical brush, that is, in the place 

 where the electric smell was most distinctly perceptible. 

 After the machine had been worked continuously for 

 four hours the strip appeared bleached as you see it. 

 (You will perhaps be interested to learn that the 

 strip which I am sending you is the very one with 

 which I for the first time proved the bleaching power 

 of the electrical odour, and that this first experiment 

 was performed on the 7th of April 1844.) 2. The 

 power possessed by the odoriferous electrical material 

 of converting potassium f errocyanide into f erricyanide. 

 A drop of ferrocyanide solution brought under the 

 above conditions assumes even after a few minutes 

 a deep yellow colour, and then on treatment with 

 pure ferrous chloride or sulphate gives a decided 

 blue precipitate. After a thousand turns of my 

 machine, a drop of such a solution gives a dark 

 blue precipitate. 3. The power possessed by the 

 electrical odour of almost instantly turning starch 

 paste containing potassium iodide blue. This power 

 has indeed long been known, but it has been errone- 

 ously interpreted ; for the separation of iodine does 

 not depend on the electrical decomposition of the 

 haloid salt, nor essentially on the formation of nitric 



