WATSON ON THE LEYDEN JAR. 533 



son, "what I have myself found out," that the electricity 

 will always describe the shortest circuit between the electri- 

 fied water and the wire of the vial which contains it, "and 

 this operation respects neither fluids nor solids, as such, 

 but only as they are non-electric (conducting) matter. 

 Thus this circuit," he adds, tracing it and using the word 

 to name the path provided by LeMonnier, "consists of the 

 two observers, the iron chain, the line of water and the 

 iron rod in the floating cork." 



Watson 1 is now well in the van. The German and the 

 French electricians, preferring to follow the leadership of 

 Winkler and Nollet, are devoting themselves chiefly to 

 contriving variations of experiments already decisive, and 

 so to heaping up a great mountain of cumulative proof. 

 Watson shows that if the amount of water in the jar is in- 

 creased even to four gallons, the stroke is not augmented 

 in strength ; that iron filings therein answer as well as 

 water, and mercury as well as iron filings. The specific 

 gravity of the material in the jar he thus discovers has no 

 influence. He states that the Ley den vial "seems capa- 

 ble of a greater degree of accumulation of electricity than 

 anything we are at present acquainted with ... by hold- 

 ing its wire to the globe in motion, the accumulation being 

 complete, the discharge runs off from the point of the wire 

 as a brush of blue flame." 



Watson now, as the result of all his observations, pro- 

 pounds a theory which was generally accepted by the 

 English philosophers. Historically, and in the light of 

 immediately ensuing events, it is of especial importance. 



The hypothesis affirms the existence of an electrical 



'Watson's papers of this period in Phil. Trans, are: No. 478, p. 41, 

 read February 6, 1746 ; No, 482, p. 388, read January 29, 1747 ; No. 484, 

 p. 695, where there is added to his paper of Februry 6, 1746, "A Sequel 

 to the Experiments and Observations," etc., read October 30, 1746. The 

 principal papers were separately published. Experiments and Observa- 

 tions, 3d Ed., London, 1746. Sequel to Experiments and Observations, 

 2d Ed,, London, 1746 : An acccount of the experiments made by some 

 gentlemen of the Royal Society, etc. London, 1748. 



