* You led your Franklin. l. 383. Dr. Franklin was the first that discovered that lighten∣ing consisted of electric matter, he elevated a tall rod with a wire wrapped round it, and fixing the bottom of a rod into a glass bottle, and preserving it from falling by means of silk-strings, he found it electrified whenever a cloud passed over it, receiving sparks by his finger from it, and charging coated phials. This great discovery taught us to defend houses and ships and temples from lightning, and also to understand, that people are always perfectly safe in a room during a thunder storm if they keep themselves at three or four feet distance from the walls; for the matter of lightning in passing from the clouds to the earth, or from the earth to the clouds, runs through the walls of a house, the trunk of a tree, or other elevated object; except there be some moister body, as an animal in con∣tact with them, or nearly so; and in that case the lightning leaves the wall or tree, and passes through the animal; but as it can pass through metals with still greater facility, it will leave animal bodies to pass through metallic ones.

If a person in the open air be surprized by a thunderstorm, he will know his danger by observing on a second watch the time which passes between the flash and the crack, and reckoning a mile for every four seconds and a half, and a little more. For sound travels at the rate of 1142 feet in a second of time, and the velocity of light through such small distances is not to be estimated. In these circumstances a person will be safer by lying down on the ground, than erect, and still safer if within a few feet of his horse; which being then a more elevated animal will receive the shock in preference as the cloud passes over. See additional notes, No. XIII.


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