120 



ELECTRICITY. 



taking it from one substance and bringing it to 

 other matters. I cannot make a piece of iron 

 or anything else heavier or lighter than it is ; 

 its cohesive power it must and does have ; but, 

 as you have seen by these experiments, we can 

 add or subtract this power of magnetism, and 

 almost do as we like with it. 



And now we will return for a short time to 

 the subject treated of at the commencement of 

 this lecture. You see here (Jig. 41) a large 



Fig 41. 



machine arranged for the purpose of rubbing 

 glass with silk, and for obtaining the power 

 called electricity ; and the moment the handle 



