Extracts from an Address by Sir W. Thomson, to the Society of Telegraphic Engineers

Abstract

I HAVE advisedly, not thoughtlessly, used the expression “terrestrial electricity.” It is not an expression we are accustomed to. We are accustomed to “terrestrial magnetism;” we are accustomed to atmospheric electricity. The electric telegraph forces us to combine our ideas with reference to terrestrial magnetism and atmospheric electricity. We must look upon the earth and the air as a whole—a globe of earth and air—and consider its electricity whether in rest or in motion. Then, as to terrestrial magnetism, of what its relation may be to perceptible electric manifestations we at present know nothing.