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Chi the Utility of fixing Liglitning Conductors in Ships. By 

 W. S. Harris, Esq. Member of the Plymouth Institution. 



1- A. THUNDER-STORM is the rcsult of a great natural action 

 subsisting between an extensive stratum of cloud, and a corres- 

 ponding portion of the earth's surface, together with the inter- 

 vening atmosphere ; and is the result of some powerful agency, 

 the nature of which is as yet undiscovered. 



2. The active principle of a thunder-storm, however, may be 

 considered as an extremely subtle species of matter universally 

 pervading nature, and distributed in bodies, in quantities pro- 

 portionate to their capacities for it, so that when accumulated 

 in and about certain bodies, and abstracted at the same time 

 from other bodies, a tendency to regain the previous state of 

 proportionate distribution is marked by a certain train of phe- 

 nomena; thus, a concentrated action is frequently set up be- 

 tween the overchai-ged and undercharged bodies, which produces 

 all the effects of a violent and terrific expansive force, for the 

 orio-inal state of proportionate distribution is often restored 

 by a rapid explosion, at which instant the most compact bodies 

 are broken ; whilst, at the same time, there is such an evolution 

 of heat, that substances directly in the line of action are some- 

 times inflamed, fused, and ignited. 



3. This easy and elementary view of electrical action may not 

 be altogether useless ; for to investigate any branch of physical 

 science with success, it is always advantageous to arrange our 

 ideas in some determinate order, by means of which the details 

 assume a clear and connected form ; for although it must be 

 admitted, that every theory is merely a way of picturing to our- 

 selves the course of nature, it may be always sufficient, and ad- 

 missible, so long as it is consistent with the observed phenomena, 

 and not contradicted by any known fact. 



4. In the progress of electrical inquiries, it has been found, 

 that some substances oppose but comparatively little resistance 

 to the passage of the electrical agency, whilst, on the contrary, 

 other substances seem to arrest its course altogether; a fact 

 which induced electricians to consider bodies as possessed of these 

 peculiar properties, and to classify them in relation to this con- 



