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charges there. Therefore it is highly dangerous in such 

 a storm, to take shelter under a tree. 



Commou fire is more or less in all bodies, as well as 

 electrical. If there be a sufficient quantity of either in 

 any body, it is inflamed. But when the quantity of 

 common fire jherein is small, there needs more electric 

 fire to inflame it. Where the quantity of common fire 

 is greater, less or" the electric will suitice. So if spirits 

 are heated, a small spark inflames them ; if they are not, 

 the spark must be greater. Sulphureous vapours, whe- 

 ther rising from the earth, or from stacks of moist hay, 

 or corn, or any other healed, and reeking vegetable, con- 

 tain abundance of common fire ; a small addition of 

 electric then will inflame them ; therefore they are easily 

 kindled by lightning. 



Any who would be clearly convinced of the nature of 

 lightning, may make the following experiment. Make 

 a small cross of two thin strips of wood, the arms being 

 just so long as to reach the four corners of a large, thin 

 silk handkerchief when extended. Tie the corners of 

 this to the extremities ot the cross ; and so you have 

 the body of a kite : add to this a proper tail, loop, and 

 string, and it will rise in the air like one made with 

 paper: but this is fitter to bear the wind and wet in a 

 storm without tearing. To the top of the cross fix a 

 sharp pointed wire, rising a foot above it ; tie a silk rib- 

 bon to the end of the twine next the hand : and where 

 the silk and twine join, fasten a key. Raise this kite 

 when a thunder-storm is coming on. But he that 

 holds the string, must stand in a porch, or under some 

 other covering that the ribbon may not be wet. He 

 must likewise take particular care, that the twine do 

 not touch the top or side of the porch. As soon as the 

 thunder-cloud comes over the kite, Hie pointed wire 

 draws the electric fire from it. The kite, and all the 

 twine are then electrified, as plainly appears by this, that 

 the loose filaments of the twine stand out every way, 

 and are attracted by an approaching finger. And when 



