Perpetual modifications are taking place in electrical condition of all matter, that when made apparent, at first may seem quite inexplicable. The excited currents flow with amazing rapidity. Their actions and re-actions baffle our calculations, and the imagination itself is bewildered by their extent and complexity. Yet by electrical tests and laboratory experiments, carefully employed, the laws of electricity are now as well known as those of any other branch of physical science, and the phenomena, if more startling, are no more mysterious than the manifestations of heat, light and gravitation. Atmospheric electricity is not different in kind from that brought into evidence by the methods of the experimenter in the laboratory, subject to his control, and much used in the arts and industries of life. The lightning that shineth from the one part under heaven to the other part under heaven, a bright light in the cloud, is the same as the electric spark from the moderately charged receiver, when the positive and negative poles are brought into contact—the same as the less intense spark excited by passing the hand rapidly over the fur on the cat’s back when the electrical conditions are favorable. The storm cloud is a vast receiver and by induction becomes at times highly charged with electricity. If the cloud is at rest, and the heated air grows moist, that which is known as sheet or heat lightning appears in frequent flashes. The imprisoned electricity leaps forth from the bosom or edge of the cloud, but as instantly gathers itself back to its source, and apparently without tension or force enough to crash through the atmosphere to any distant object. The flashes are unaccompanied by the noise of thunder, and may be but reflections on the cloud from a source far beyond. We watch them without fear of danger, and the subdued impression is that of the beautiful. Amidst the terrific grandeur of the violent thunder storm another form of lightning is seen; either the vivid flash that seems to envelop us, or zigzag, sometimes forked lines that dash across the cloud earthward, and occasionally, as in a return stroke, from the earth to the cloud.