66 FARADAY 



good an indicator as can be required. See how it rolls along, 

 traveling after the sealing-wax! If I make them smaller, of 

 course we have them running faster, and sometimes they are 

 actually attracted up into the air. Here, also, is a little 

 collodion balloon. It is so electrical that it will scarcely leave 



my hand unless to go to the 

 other. See how curiously elec- 

 trical it is ; it is hardly possible 

 for me to touch it without 



I \ I / ^ making it electrical ; and here is 



V \kjjL&' f a piece which clings to any 



FJG g thing it is brought near, and 



which it is not easy to lay down. 



And here is another substance, gutta-percha, in thin strips: 

 it is astonishing how, by rubbing this in your hands, you 

 make it electrical ; but our time forbids us to go farther into 

 this subject at present; you see clearly there are two kinds of 

 electricities which may be obtained by rubbing shellac with 

 flannel or glass with silk. 



Now there are some curious bodies in nature (of which I 

 have two specimens on the table) which are called magnets 

 or loadstones; ores of iron, of which there is a great deal 

 sent from Sweden. They have the attraction of gravitation, 

 and attraction of cohesion, and certain chemical attraction; 

 but they also have a great attractive power, for this little key 

 is held up by this stone. Now that is not chemical attraction ; 

 it is not the attraction of chemical affinity, or of aggregation 

 of particles, or of cohesion, or of electricity (for it will not 

 attract this ball if I bring it near it), but it is a separate and 

 dual attraction, and, what is more, one which is not readily 

 removed from the substance, for it has existed in it for ages 

 and ages in the bowels of the earth. Now we can make 

 artificial magnets (you will see me to-morrow make artificial 

 magnets of extraordinary power). And let us take one of 

 these artificial magnets and examine it, and see where the 

 power is in the mass, and whether it is a dual power. You 

 see it attracts these keys, two or three in succession, and it 

 will attract a very large piece of iron. That, then, is a very 

 different thing indeed to what you saw in the case of the 

 shellac, for that only attracted a light ball, but here I have 



