278 oN GALVANIC PHENOMENA. 



in contact with each other, separated by pieces of wet cloth, 

 that pile, beside the motions of the gold leaves at its extre- 

 mities when free, produced chemical effects in the water of 

 the glass tubes when forming the circuit ; but, by substitut- 

 ing for the wet pieces of cloth pieces of the same cloth, new, 

 and without wetting them, I had the same motions of the 

 gold leaves at its extremities, only less, and not the smallest 

 appearance of chemical effect in the water of the glass tubes. 

 Search for a This first observation opened a new field to my view. 

 iSdlfcf "^ Havin g conjectured, that wool, the material of the cioth I 

 used, had in itself very little conducting faculty, and that 

 it became a good conductor only by being wet, I undertook 

 a long series of experiments for finding out what substance, 

 Vegetable no * w ^ a ^ c > was tne Dest conductor. I found in general, 

 best. that vegetable substances were, better, conductors than animal 



ones; and among the former, plain writing paper having 

 produced as much effect as any other, I fixed upon it, as 

 being easily cut to the size of the metallic plates. 

 Experiment I then made tne Exp. 20, which concludes the paper 

 wit th«. in your Journal. I mounted again the pile of 76 groups 

 of zinc aud silver plates in contact, separated only by pieces 

 of paper. ThispiVe produced as great electrical signs at its 

 extremities, as that with the wet cloth, but not the smallest 

 chemical effect appeared in the water of the tubes, when 

 they connected these extremities. Thus were demonstrated 

 ihe conclusions, which I had deduced from the phenomena 

 of the pile itself. 

 Steps t« which My paper in your Journal for August 1810 describes 

 this discovery the steps, to which this first discovery led roe; which pro- 

 gress, had Dr. Maycock known it, would undoubtedly 

 have struck him, as bringing to view an absolutely new 

 field in experimental philosophy, not only by ascertaining 

 the distinct causes of electrical and chemical effects in the 

 pile (as indicated by the preceding experiment); but by 

 this important phenomenon, that the motions of the gold 

 leaves are very different at different times, without any 

 connection with the difference of either heat or moisture^ 

 which changes were to be attributed to changes in the 

 electrical state of the ambient air, from the following facts, 

 leading to meteorology. 



W« 



