J38 THUNDER & LIGHTNING. [Lesson XXII. 



the present state of knowledge will permit. Many 

 observations and experiments tend to prove that 

 some clouds are in a positive, and some in a nega- 

 tive state of electricity; and from other experiments 

 ithas been inferred that the quantity of electric mat- 

 ter in a common Thunder-storm, is inconceivably 

 great, considering how many pointed bodies, as 

 steeples and trees, are continually drawing it off, 

 and what a prodigious quantity is repeatedly dis- 

 charged to or from the earth. This matter is in 

 such abundance, that it is thought impossible for 

 any number of clouds to contain it all, so as either 

 to receive or discharge it. During the progress 

 and increase of a storm-, it has been observed, that 

 though the Lightning frequently struck to the 

 earth, the same clouds were ready the next mo- 

 ment to make a still greater discharge: whence it 

 is concluded, that the clouds serve as conductors 

 to convey the electric fluid from those parts of the 

 earth that are overloaded with it, to those that are 

 exhausted of it. The same cause by which a cloud 

 is first raised, from vapours in the atmosphere, 

 draws to it those which are already formed, and 

 still continues to form new ones, till the whole col- 

 lected mass extends sufficiently far to reach a part 

 of the earth where there is a deficiency of the elec- 

 tric fluid, at which place the electric matter will 

 discharge itsrlt on the earth. A channel of com- 

 munication being thus formed, a fresh supply of 

 electric matter is raided from the overloaded part, 

 which continues to be conveyed by the medium of 

 the clouds, till the equilibrium of the fluid is re- 

 stored 



