34 THUNDER LIGHTNING. 



When, for example, a glass tube is rubbed 

 with a woollen cloth ; small pieces of paper, 

 straw, feathers, or other light bodies held over 

 it,, will be drawn towards the tube, and driven 

 from it. If you put your finger to this tube in 

 the dark, you see a spark, hear a snap, and feel 

 a slight pricking in the finger. If you rub the 

 tube hard for some time, and then hold it near 

 your face, you feel a sensation, as if a cobweb 

 was spread upon your check. Similar effects 

 are produced by other substances when they are 

 rubbed ; such as amber, sulphur, porcelain, and 

 sealing-wax. 



The observation of these facts led to the con- 

 struction of a machine, by which electricity can 

 easily be produced, and which is called the elec- 

 trical machine. By means of this machine, 

 sparks have been produced of such power as, 

 in an instant, to melt metals and to kill animals. 

 This electric matter subsists in the clouds called 

 thunder-clouds, from which it issues in the form 

 of flashes of fire, which are called lightning. 

 The noise which usually follows the flash, or 

 the lightning, we call thunder. 



The electric flame, which we call lightning, 

 when it strikes a tree or a house, either damages 

 or destroys it entirely, or sets it on fire. If it 

 strikes men or beasts, it either stuns, maims, or 

 kills them. God, however, in his mercy, generally 

 protects his creatures from harm ; and in the 

 benefits that attend thunder-storms compensates 



