40 COHESION. 



tides of the wire, just as in pantomimes they 

 sometimes suspend gentlemen and damsels. 



How can we make this attraction of the par- 

 ticles a little more simple ? There are many 

 things which if brought together properly will 

 show this attraction. Here is a boy's experi- 

 ment (and I like a boy's experiment). Get a 

 tobacco-pipe, fill it with lead, melt it, and then 

 pour it out upon a stone, and thus get a clean 

 piece of lead (this is a better plan than scraping 

 it scraping alters the condition of the surface 

 of the lead). I have here some pieces of lead 

 which I melted this morning for the sake of mak- 

 ing them clean. Now these pieces of lead hang 

 together by the attraction of their particles, and 

 if I press these two separate pieces close together, 

 so as to bring their particles within the sphere 

 of attraction, you will see how soon they become 

 one. I have merely to give them a good squeeze, 

 and draw the upper piece slightly round at the 

 same time, and here they are as one, and all 

 the bending and twisting I can give them will 

 not separate them again ; I have joined the 

 lead together, not with solder, but simply by 

 means of the attraction of the particles. 



This however is not the best way of bringing 



