ELECTRIC FLUID. 



consisting of two simple fluids having antagonistic properties 

 which when, in combination neutralise each other, but which 

 recover their activity by decomposition. Others again regard it 

 not as a specific fluid which moves through space, but as a 

 phenomenon analogous to sound, and think that it is only a series 

 of undulations or vibrations that are propagated through a highly 

 elastic medium which produce the various electrical effects just 

 as the pulsations of the atmosphere produce all the effects of 

 sound. 



13. Happily these difficult discussions are not necessary to the 

 clear comprehension of the laws which govern the phenomena, 

 upon which electric telegraphy depends. It will nevertheless for 

 the purposes of explanation be convenient to use a system of 

 language, which implies the existence of a certain fluid which we 

 shall call the electric fluid, capable of moving over certain bodies, 

 and being obstructed or altogether stopped by others, and which 

 by its presence or proximity produces certain definite effects, 

 mechanical and chemical. 



14. Whether the electric agency be or be not a material fluid 

 for our present purpose is unimportant. It is enough that it 

 comports itself as such, and that the properties or effects which we 

 shall impute to it are such only as it is ascertained by observation 

 and experiment to possess or produce. 



15. However various the forms may be which invention has 

 conferred upon electric telegraphs, their efficiency in all cases 

 depends on our power to produce at will the following effects : 



1st. To produce or develop the electric fluid in any desired 

 quantity, and of the necessary quality. 



2nd. To transmit it with celerity to any required distance, 

 without injuriously dissipating it. 



3rd. To cause it upon its arrival at any assigned point to 

 produce some sensible effects, which may serve the purpose of 

 written or printed characters. 



16. The electric fluid is deposited in a latent state in unlimited 

 quantity in the earth, the waters, the atmosphere, and in all 

 bodies upon the earth, whether solid, liquid, or gaseous. It is 

 disengaged and rendered active by various causes, natural and 

 artificial. The mutual friction of bodies, contact and pressure, 

 the contiguity or contact of bodies having different temperatures, 

 the chemical action of bodies one upon another, the action of 

 magnetic bodies on each other, and on bodies susceptible of mag- 

 netism, are severally causes of the development of the electric 

 fluid in greater or less quantity. 



Founded upon these phenomena, various apparatus have been, 

 contrived, by means of which the electric fluid may be evolved 



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