Royal Institution. 137 



ihcy must he continually in operation in external nature; 

 their grandeur and sublimity are exhibited in the thunder 

 storm ; and in their more tranquil agencies they minister 

 to the order of ihe terrestrial system, and perform slowly 

 and silently important functions in theoeconomy of things." 



Electricity, by influence or induction, is difTerent for 

 different subjitanccs; and the phaenomena of electricity, by 

 influence, exhibit the difference between conductors, im- 

 perfect conductors, and non-conductors. It is also on the 

 principle of induction, combined in some cases with that 

 of primary excitation, that the powers of the instruments 

 for accuiiuilating electricity depend, as in the Leydenjar 

 and V^)itaic apparatus. 



Mr, Davy exhibited the powers of the Voltaic instru- 

 ment by some brilliant experiments; medals were fused 

 upon the surface of water and oil of turpentine, and burnt 

 in contact with them. He stated that the maximum of 

 heat was at the positive electrical surface ; and he exhibited 

 an experiment in which, though the most brilliant light 

 was at the negative surface, yet the ignition was infinitely 

 greater at the positive. 



The Professor pointed out the analogy between the Vol- 

 taic battery and the organs of the torpedo and gymnotus. 

 '• These mean animals," said he, " in the bosom of the 

 waters, are found armed with the power that produces 

 lightning and thunder. The more the resources of art are 

 extended, the more analogies to them are found in nature, 

 which offers, as it were, the archetypes of even our happiest 

 and most extraordinary invention." 



In speaking of lightning, the Professor said, that rods 

 intended to preserve buildings from its effects should be at 

 least half an inch thick, and coated at top and bottom with 

 platina, to prevent ihe effects of the weather. They should 

 also terminate, if possible, in a moist stratum of earth. 



In considering the applications of electrical science to 

 explain natural phrenomena, Mr. Davy said, that the brilli- 

 ant and astonishing discoveries made known in this science 

 in the middle of last century, attracted the attention of 

 speculative as well as of experimental philosophers; and at- 

 tempts weie mailc to explain all the great and extraordinary 

 phienomena of nature by electrical agencies. " New prin- 

 ciples," said he, " wiicn first discovered, are always extend- 

 ed too far; the imagination, like the eye, is dazzled by no- 

 vel and brilliant lights, and time is required before objects 

 are seen in their true relations or proper coloins." 



The natural appearances which may with probability be 

 altribuled to, or supposed to be connected with, electrical 



effects. 



