28 GKAYITATION. 



fall as fast as anything else. And if I suspend 

 the bottle containing the gold leaf to a string, 

 and set it oscillating like a pendulum, I may 

 make it vibrate as hard as I please, and the 

 gold leaf will not be disturbed, but will swing 

 as steadily as a piece of iron would do; and I 

 might even swing it round my head with any 

 degree of force, and it would remain undis- 

 turbed. Or I can try another kind of experi- 

 ment: if I raise the gold leaf in this way 

 [pulling the bottle up to the ceiling of the 

 theatre by means of a cord and pulley, and 

 then suddenly letting it fall to within a few 

 inches of the lecture table], and allow it then 

 to fall from the ceiling downwards (I will put 

 something beneath to catch it, supposing I 

 should be maladroit), you will perceive that 

 the gold leaf is not in the least disturbed. The 

 resistance of the air having been avoided, the 

 glass bottle and gold leaf all fall exactly in the 

 same time. 



Here is another illustration: I have hung 

 a piece of gold leaf in the upper part of this 

 long glass vessel, and I have the means, by a 

 little arrangement at the top, of letting the 

 gold leaf loose. Before we let it loose we will 



