The distance of a thunder-storm and its consequent danger can easily be estimated. As light travels at the rate of 192,000 miles in a second of time, its effects may be considered as instantaneous within any moderate distance. Sound is transmitted at the rate of only 1142 feet in a second. By observing, therefore, the time which intervenes between the flash of lightning and the thunder which accompanies it, a very near calculation may be made of its distance. 812. _Stroke of Lightning._--Throw cold water upon them as soon as possible. It will often restore persons struck by lightning when apparently insensible, or even dead. 813. _A few Concise Rules for the Recovery of Persons apparently Drowned._--The body on being taken out of the water, should be conveyed to the nearest house, _in the gentlest manner possible_; the wet clothes must be removed, and the body well dried with a towel; it must then be placed on a mattress, laid on a table of proper height and length. Care must always be taken to lay the head considerably higher than the extremities, and to place the body on the right side. The lungs should be inflated with a pair of bellows, not forcibly, but gradually, so as to imitate the action of respiration. Do not place the body in a high degree of heat; (below 98 degrees of Fahrenheit's scale is the best temperature,) clear the apartment of all supernumerary persons, and let the windows and doors be open, to admit a free circulation of air. Apply friction, _after the lungs have been expanded_, with the hand only, or with a little oil on the fingers. No injections are necessary, nor emetics, except in particular cases: bleeding is also a doubtful remedy: electricity, _in judicious hands_, may prove highly beneficial. Let no rolling of the body be used with a view of emptying it of water; there is no water present, or scarcely any. The heart being overloaded with blood, may be burst by this injudicious proceeding, and more mischief has been done by tossing and rolling the body, than by any other erroneous treatment. Hot water, in bottles, may be applied to the feet and ankles, as soon as respiration commences: when the blood begins to circulate, heat may be gradually increased, and the patient removed to a warm bed, where he must be carefully watched till the action of the heart be completely restored.