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XVIII. On the supposed Identity of the Agent concerned in the 

 Phenomena of ordinary Electricity, Voltaic Electricity, Electro- 

 magnetism, Magneto-electricity , and Thermo-electricity. By 

 M. Donovan, Esq., M.R.I.A.* 



Section I. — On the Constitution of the Electric Fluid. 



TO refer the greatest number of effects to the least number 

 of causes has been a favourite effort with those who ima- 

 gine that, by so doing, they vindicate and hold up to admiration 

 what they call the simplicity of Nature's operations. It may be 

 questioned, however, whether the faculties of man enable him 

 to perceive and appreciate what is thus alleged to be a perfection. 

 It being as easy for the Almighty to bring into operation a mil- 

 lion of causes as one, the grounds are not obvious on which sim- 

 plicity has been imagined an attribute of Divine agency. Ts T or 

 does it appear what is meant by the term when thus employed ; 

 for if we diminish the number of agents, we must increase the 

 number of tbeir properties, in order to explain, with, any degree 

 of probability, the diversity of natural phsenomena ; hence no- 

 thing is thereby simplified, and no advantage gained. 



Simplicity does not seem to be the order of nature : scarcely 

 any object is simple; almost everything is compound. The 

 thousands of mineral substances that constitute the mass of 

 the globe are numerously compounded ; they rarely consist of 

 single elements ; and the waters which surround it are com- 

 posed of a variety of ingredients. Animals and plants, if we 

 consider their component parts in conjunction with their pro- 

 perties, as constituting living organizations, are complex beyond 

 all comprehension. Even the atmosphere, and the solar rays 

 which penetrate it, are of the same heterogeneous structure. If 

 the sun's light be thus of compound constitution, why should 

 we doubt that the allied element, electricity, partakes of the uni- 

 versal character which the Almighty has impressed on his works ? 



This question brings us to the immediate object of the first 

 part of the present essay — Is electricity a simple element ? 



In the existing state of knowledge, it is impossible to come to 

 any positive determination. It appears tome, however, that the 

 agent called the electric fluid falls within the general analogy of 

 nature ; that far from being a homogeneous elastic medium, as 

 it is generally conceived to be, it consists of several elementary 

 constituents, each possessing different properties. The nature 

 of this agent may be considered without reference to the ques- 

 tion of its being matter, or motion of matter, or of an sethcreal 

 fluid : motion may be compound as well as matter. 



* Communicated by the Author. 



