IT'S OH EEECftfRO-CIIEMICAL EXPERIMENTS, 



illustrating this action is the following. To a pint of water 

 add two or three drops of sulphuric acid, and infuse in it 

 as many minced leaves of red cabbage as it will cover. I» 

 a day or two, the water will be tinged of a fine red colour. 

 Decant the liquor, and preserve it in a bottle closely stop- 

 ped. When the experiment is to be performed, a portion 

 of the red tincture is to be neutralized, by carefully adding 

 a few drops of ammonia, till it assumes a blue colour. Two 

 watch glasses connected by a moistened fibre of cotton, or 

 bibulous paper, are to be filled with this red fluid, and 

 placed in the circuit by connecting one of them with the 

 negative, and the other with the positive wire of the bat- 

 tery. In a short time, this alkali will be attracted by the 

 negative wire, and the fluid which surrounds it will conse- 

 quently assume a green colour; while the positive wire, at- 

 tracting the acid, converts the fluid which surrounds it to a 

 fine red. In about half an hour the transfer will be com- 

 plete, the fluid in the negative cup being of a beautiful 

 green, and that in the positive of a bright red. If the si- 

 tuation of the wires are now reversed, so that the cup which 

 was positive may become negative, and that which was ne- 

 gative assume a positive state, the colours will again change; 

 the green will first become blue, and then red; and the red, 

 after first returning to its original blue, will become green. 

 This alternate transfer, which may be several times repeated 

 with one charge, I have frequently produced by a trough of 

 only 30 pairs of plates of 2 inches square. 

 Apology for J h ave been rather particular (perhaps it may be thought 



too much so) in the account I have given of these experi- 

 ments, but I do not write for the instruction of the expe- 

 rienced chemist, and I am inclined to think the tyro will 

 thank me for having attempted to diminish the difficulties 

 of his pursuit. I am at present engaged in the extension 

 of these experiments, and in the prosecution of others con- 

 nected with the same inquiry, and intend shortly to publish 

 ah elementary work on the subject, in which I shall attempt 

 the arrangement of a systematic series of familiar experi- 

 ments, in illustration of the several phenomena. 



8 Princes. Street, Cavendish Squmre f 

 Sept. 21^ 1809- 



IV. 



in muteness. 



