102 Mr. H. Wilde's Experimental Researches 



now insufficient to make the same length of thin wire hotter than 

 could be endured by the finger, the result thereby indicating a 

 greater amount of resistance to the passage of the current into 

 the earth than that which the salt water in the tub presented to 

 the passage of the current between the same conductors when in 

 the form of a double coil. This difference of resistance to the 

 passage of the current, according as the conductors were extended 

 in the sea or coiled up together in the tub of salt water, coincides 

 with the difference which we have already observed when the 

 same conductors were coiled up in the tub of fresh water and 

 extended separately in the canal (115, 147). 



178. To sum up the results of these experiments, as far as we 

 have gone, on the transmission of electric currents through 

 liquids contained in insulated vessels, and those forming part of 

 the terrestrial globe : — By operating in both cases with the same 

 electromotors and arrangement of conductors, all the various 

 phenomena of conduction and resistance obtained in the tub of 

 fresh and salt water were identical in kind with those obtained 

 in the canal and in the sea, the difference in degree being due to 

 the close proximity of the twin conductors when in the form of 

 a double coil in the tub, which, as we have seen, augmented the 

 amount of discharge from the electromotors above that which 

 the normal action of the earth induced when these same conduc- 

 tors were extended separately in contact with it. From the in- 

 creased amount of discharge obtained from the 10-inch intensity- 

 armature when the double coil was immersed in dilute sulphuric 

 acid (154), and the absolute stoppage of the current when a 

 similar double coil was immersed in a vessel of oil (166), we may 

 justly infer that similar extremes of conduction and resistance 

 would manifest themselves if these liquids formed part of the 

 terrestrial globe, so that the earth would consequently become 

 either a conductor or an insulator, according to the nature of the 

 liquids incorporated with its substance. Again, the resistance 

 which the earth, whether forming the bed of the sea or of the 

 canal, presents to the passage of a current of low intensity, and 

 the diminution of this resistance by an increase of the intensity 

 of the current, coincide with the same order of resistances and 

 intensities of the current observed in the electrolyzation of liquids 

 in insulated vessels. We have also seen that the transmission of 

 the current from even the most feeble of the electromotors used 

 in these experiments, either through dilute sulphuric acid or dis- 

 tilled water, was in every case attended by the electrolyzation of 

 the liquids into which the electrodes were plunged. Hence we 

 may justly conclude, even without the exhibition of the electro- 

 lytic products themselves (which will, however, be shown in ex- 

 periments to be hereafter adduced (198-205)), that the transmis- 



