140 ELECTRICITY. 



about the ends, edges, corners, or points, than in other places. Its expansive 

 force at such parts is therefore greater than elsewhere, and will exceed the 

 atmospheric pressure, and escape when at other parts of the surface it is 

 retained. 



This theory will be explained in the present work, as far as its development 

 is consistent with the object of this volume. It will not, therefore, be need- 

 ful to enlarge upon it further in this place. It may, however, be asked why it 

 is, seeing that the theory of two fluids is sufficient for the explanation of all 

 the phenomena to which it has yet been applied, and that, on the other hand, 

 the theory of a single fluid fails to afford any satisfactory or accurate explana- 

 tion of so many phenomena, the latter theory, nevertheless, still has followers, 

 and that even among electricians, whose opinions cannot be regarded other- 

 wise than with sentiments of respect, it is still clung to as the hypothesis best 

 entitled to reception and confidence ? It is not easy to assign any sufficient rea- 

 son for this, unless one can be found in the profound and abstruse nature of the 

 mathematical principles by the aid of which alone the effects are capable of be- 

 ing expressed. When it is remembered that, until very recently, electricity was 

 regarded as exclusively a part of experimental physics ; that researches in it 

 were chiefly carried on by persons engaged in chemical investigations ; that, 

 from the nature of their studies and pursuits, such persons rarely cultivated 

 even the elements of mathematics, and almost never pursued analytical science 

 into those more profound parts which are now indispensable for the solution of 

 the class of problems which electricity has presented it cannot be matter of 

 much surprise that reasoning which is incapable of being expressed save by 

 symbols of which the force and import must be unintelligible to the great mass 

 of such persons, should fail to carry conviction to their understanding. To 

 arrive at such conviction, they must either commence their education anew, or 

 be content to receive those new doctrines on their faith in the assurance of 

 those who are capable of investigating them. Either side of such an alterna- 

 tive is never very willingly embraced. 



Having now followed the progress of discovery in this part of electrical sci- 

 ence to that point at which all subsequent researches must be regarded as the 

 labor of our contemporaries, the province of the historian ceases. Whatever 

 has been effected more recently will properly form a part of the subject matter 

 of the volume here presented to the reader, of which it is hoped that a brief 

 exposition and analysis of the researches of contemporary philosophers will 

 form not the least interesting and useful portion. 



L. 



