Science recognizes a more fundamental world than that of matter. This is the electro-magnetic world which underlies the material world and which, as Professor Soddy says, probably completely embraces it, and has no mechanical analogy. To those accustomed only to the grosser ideas of matter and its motions, says the British scientist, this electro-magnetic world is as difficult to conceive of as it would be for us to walk upon air. Yet many times in our lives is this world in overwhelming evidence before us. During a thunderstorm we get an inkling of how fearfully and wonderfully the universe in which we live is made, and what energy and activity its apparent passivity and opacity mark. A flash of lightning out of a storm-cloud seems instantly to transform the whole passive universe into a terrible living power. This slow, opaque, indifferent matter about us and above us, going its silent or noisy round of mechanical and chemical change, ponderable, insensate, obstructive, slumbering in the rocks, quietly active in the soil, gently rustling in the trees, sweetly purling in the brooks, slowly, invisibly building and shaping our bodies--how could we ever dream that it held in leash such a terrible, ubiquitous, spectacular thing as this of the forked lightning? If we were to see and hear it for the first time, should we not think that the Judgment Day had really come? that the great seals of the Book of Fate were being broken? What an awakening it is! what a revelation! what a fearfully dramatic actor suddenly leaps upon the stage! Had we been permitted to look behind the scenes, we could not have found him; he was not there, except potentially; he was born and equipped in a twinkling. One stride, and one word which shakes the house, and he is gone; gone as quickly as he came. Look behind the curtain and he is not there. He has vanished more completely than any stage ghost ever vanished--he has withdrawn into the innermost recesses of the atomic structure of matter, and is diffused through the clouds, to be called back again, as the elemental drama proceeds, as suddenly as before. All matter is charged with electricity, either actual or potential; the sun is hot with it, and doubtless our own heart-beats, our own thinking brains, are intimately related to it; yet it is palpable and visible only in this sudden and extraordinary way. It defies our analysis, it defies our definitions; it is inscrutable and incomprehensible, yet it will do our errands, light our houses, cook our dinners, and pull our loads. How humdrum and constant and prosaic the other forces--gravity, cohesion, chemical affinity, and capillary attraction--seem when compared with this force of forces, electricity! How deep and prolonged it slumbers at one time, how terribly active and threatening at another, bellowing through the heavens like an infuriated god seeking whom he may destroy!