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LI. On the Conductibility of the Earth for Electricity, 

 By James Napier, Esq* 



\ T the recent meeting of the British Association in Edin- 

 -^*» burgh, Professor Matteucci communicated a paper upon 

 the conductibility of the earth, in which are given many inter- 

 esting experiments; but it is there stated that hitherto "nothing 

 had been known of the laws and theory of this singular phe- 

 nomenon." I thought that the theory of the conductibility of 

 the earth for electricity had been long known to men of science 

 in this country, and the cause to be, as Mr. R. Hunt stated 

 at the conclusion of the paper, depending upon the water con- 

 tained in the superficial stratum of the earth. In corroboration 

 of Mr. Hunt^s remarks, I send you the results of a few ex- 

 periments made in 1843 upon this subject, which were not 

 published at the time, from the belief that the conclusions they 

 led to were previously well known. 



My object in these experiments was to apply the electricity 

 obtained from the earth to the deposition of metals; the firet 

 experiments were, placing pieces of zinc and copper in the 

 earth so as to constitute a battery ; but I was soon struck with 

 the fact that it did not appear of any consequence, as regards 

 the quantity and power of the electric current, whether these 

 metals were placed only a few inches apart or a number of feet, 

 or yards, or acres, or whether there stood between them trees, 

 houses, or streets ; indeed many of the experiments were made 

 by having one plate of metal imbedded in the garden in front 

 and another in the garden behind my house, which had a sunk 

 flat ; and there was no apparent difference in the results ob- 

 tained under these conditions to those obtained when both 

 metals were imbedded a few inches apart in one garden. Tne 

 question which suggested itself from these results was, whether 

 this conducting power was dependent upon the nature of the 

 materials composing the earth ? To ascertain this, a plate of 

 zinc and copper were laid upon a large table a few inches apait, 

 and connected by a wire. When the table was wet there was 

 a current passing, but not when dry; when these plates were 

 imbedded in sawdust and in sand, a current was always ob- 

 tained when these materials were wet, but ceased when they 

 were dry. A large vessel was then filled with earjh from the 

 garden, and a zinc and copper plate imbedded in it, and the 

 whole placed in such a condition as to allow the earth to dry 



* Communicated by the Author. 



