WHAT IS FORCE? 5 



paper is immediately moved towards the shell- 

 lac, and by now drawing the latter away, the 

 paper falls over without having been touched 

 by anything. You see in the first illustration 

 I produced an effect than which nothing could 

 be commoner I pull it over now, not by 

 means of that string or the pull of my hand, but 

 by some action in this shell-lac. The shell-lac, 

 therefore, has a power wherewith it acts upon 

 the sheet of paper ; and as an illustration of 

 the exercise of another kind of power, I might 

 use gunpowder with which to throw it over. 



Now, I want you to endeavour to comprehend 

 that when I am speaking of a power or force, 

 I am speaking of that which I used just now to 

 pull over this piece of paper. I will not embar- 

 rass you at present with the name of that power, 

 but it is clear there was a something in the 

 shell-lac which acted by attraction, and pulled 

 the paper over \ this, then, is one of those things 

 which we call power, or force; and you will 

 now be able to recognise it as such in whatever 

 form I show it to you. We are not to suppose 

 that there are so very many different powers ; 

 on the contrary, it is wonderful to think how 

 few are the powers by which all the phenomena 



B 3 



