148 COKKELATION OF THE PHYSICAL FORCES. 



since I was born, that the discovery of the 

 relations of these two forces of electricity and 

 chemical affinity to produce magnetism have 

 become known. Philosophers had been sus- 

 pecting this affinity for a long time, and had 

 long had great hopes of success for in the 

 pursuit of science we first start with hopes and 

 expectations; these we realise and establish 

 never again to be lost, and upon them we found 

 new expectations of further discoveries, and so 

 go on pursuing, realising, establishing, and 

 founding new hopes again and again. 



Now observe this: here is a piece of wire 

 which I am about to make into a bridge of force, 

 that is to say, a communicator between the two 

 ends of the battery. It is copper wire only, and 



Fig. 51. 



is therefore not magnetic of itself. We will 

 examine this wire with our magnetic needle 



