Page:Various Forces of Matter.djvu/160

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143
CORRELATION 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 suspecting 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.

Fig. 51.

It is copper wire only, and is therefore not magnetic of itself. We will examine this wire with our magnetic needle