CHAPTER VIII
EFFECTS OF THE CURRENT
The term “electric current,” in the present state of our knowledge, should be regarded as denoting the existence of a state of things in which certain definite experimental effects are produced, for some of which there certainly is no analogy exhibited in ordinary hydraulic currents. The following are the most important of these effects:
1. Thermal effect; 2. Magnetic effect; 3. Chemical effect.
It is rather to these effects than to any imaginary current flow in the conductor that the mind of the reader should be directed.
With this preliminary caution, which should never be lost sight of, the use of familiar words and expressions connected with the flow of water in pipes is justified in order to avoid roundabout and cumbrous phrases which, though perhaps more nearly in accord with present knowledge of the facts, would not tend to clearness or conciseness.
The three most important effects of the current just mentioned, may be presented in more detail as follows:
1. The Thermal effect:—
The conductor along which the current flows becomes heated. The rise of temperature may be small or great according to circumstances, but some heat is always produced.
2. The Magnetic effect;