anJCanfiru&hi^ Lighintng Rods, 97 



poiitlre and negative, progress and dlredlion are properties not 

 without their evidence, jet want explanation. - , m " 



From the experiments and observations, which I have 

 made,l am inclined to think, that upon the fiidden ailem- 

 blage of the clouds, in the time of a thunderftorm, the elec- 

 trical fluid is excited and difpofed, unequally, injirata^ at dif- 

 ferent altitudes, which are continually varying in their fitua-' 

 tion, according as the explofions'of th^ lightning flilft the power' 



of attradlion ; and it is'higlily prol^abie, that there are, at 

 thofe times, Jif%ta of non conducfllng atmofphere', Interven- 

 ing between oxhtv Jirata differently afFe<5led. Now if this, 



be really the cafe, and the height of the points of the rod do 



not happen to correfpond with the level of 'dxzjiratiim affe<5l- 

 ed, the ufe oi the rod will in a great meafure be loft. 



It is a well known fa(5l, that the ele^flrical fluid enters and 



■ b 



efcapes by points and angles more readily than hj ipherical 



terminations. ^ 



% 



w 



-* 



From thefe circumllances I think it mufl appear, that an 

 eleflrical rpd, prepared like the farnple which accompanies 



T 



this paper, would be better adapted to ec^uahze the fluid than 

 the common cylindrical rods in ufe ; for the iniinity of 

 points, or rather the continuation of them from the bottom 

 to the top o£ the rod, provides for the entrance or efcape of 

 the fluid of 2,njjlratum, however aiFeded, at any level, at or 

 below the fummit points ; which, I think, muft be confidered 



aa additional advantage j at any rate, fuch a rod will anfwer 



o 



as- 



