A lightning flash probably lasts from about 1/100,000 to 1/1,000,000 of a second, and in the majority of cases the discharge is oscillatory; that is to say, it passes several times backwards and forwards between two clouds or between a cloud and the Earth. At times it appears as though we could see the lightning start downwards from the cloud or upwards from the Earth, but this is an optical illusion, and it is really quite impossible to tell at which end the flash starts. Death by lightning is instantaneous, and therefore quite painless. We are apt to think that pain is felt at the moment when a wound is inflicted. This is not the case however, for no pain is felt until the impression reaches the brain by way of the nerves, and this takes an appreciable time. The nerves transmit sensations at a speed of only about one hundred feet per second, so that in the case of a man killed by a bullet through the brain, no pain would be felt, because the brain would be deprived of sensibility before the sensation could reach it. Lightning is infinitely swifter than any bullet, so life would be destroyed by it before any pain could be felt. On one occasion Professor Tyndall, the famous physicist, received accidentally a very severe shock from a large battery of Leyden jars while giving a public lecture. His account of his sensations is very interesting. “Life was absolutely blotted out for a very sensible interval, without a trace of pain. In a second or so consciousness returned; I saw myself in the presence of the audience and apparatus, and, by the help of these external appearances, immediately concluded that I had received the battery discharge. The intellectual consciousness of my position was restored with exceeding rapidity, but not so the optical consciousness. To prevent the audience from being alarmed, I observed that it had often been my desire to receive accidentally such a shock, and that my wish had at length been fulfilled. But, while making this remark, the appearance which my body presented to myself was that of a number of separate pieces. The arms, for example, were detached from the trunk, and seemed suspended in the air. In fact, memory and the power of reasoning appeared to be complete long before the optic nerve was restored to healthy action. But what I wish chiefly to dwell upon here is, the absolute painlessness of the shock; and there cannot be a doubt that, to a person struck dead by lightning, the passage from life to death occurs without consciousness being in the least degree implicated. It is an abrupt stoppage of sensation, unaccompanied by a pang.” Occasionally branched markings are found on the bodies of those struck by lightning, and these are often taken to be photographic impressions of trees under which the persons may have been standing at the time of the flash. The markings however are nothing of the kind, but are merely physiological effects due to the passage of the discharge.