HYPOTHESIS OF TWO FLUIDS. 429 



lightning. It is further stated by De Saussure 

 and many others, that atmospheric electricity is 

 constantly changing from positive to negative, 

 which is also quite inconsistent with the hypo- 

 thesis of two fluids.* 



Theoretical Views of Caloric and Electricity. 



It is only by extending our knowledge of 

 nature, that we are enabled to trace an endless 

 diversity of apparently isolated effects to some 

 principle which connects and governs them ; or 

 to distinguish an unknown cause from the indi- 

 vidual and ever varying phenomena it produces. 

 The most signal and delightful triumphs of phi- 

 losophy spring from the perception of analogies 

 that seem remote and obscure, until closely ana- 

 lyzed. From the imperfect outline which has 

 been already presented of this vast and compli- 

 cated subject, it is obvious that all the opera- 

 tions of nature are so intimately connected, that 

 we cannot make any substantial progress in the 

 discovery of general principles without ascending 

 to the primary source of all physical power. 



* It is related by Van Marum, that the doctrine of two elec- 

 tric fluids became general in France from the fact, that M. Hauy 

 was ordered by Napoleon to prepare a Treatise on Natural Phi- 

 losophy for the use of the Polytechnic School, and not having 

 time for reflection, he hastily adopted Coulomb's version of the 

 two fluids. Well might Count Oxenstiern say, to his son, come 

 and see with how little wisdom the world is governed. 



