In about the middle of the eighteenth century the identity of lightning with electricity was fully ascertained, and since then the most sublime and startling phenomena of our thunder storms are better understood. Under certain contingencies they must occur. Since the different clouds or portions of the same cloud are charged with different electricities, positive and negative, when these by the winds are brought near each other, or rolled together, fierce explosions follow, and great electrical changes take place in the clouds. Vast supplies of the imprisoned fiery fluid leap from strata to strata, or, if the distance is not too great, and the earth is at the same time strongly electrified, crash down to it through whatever sufficient conductors are found. If those not sufficient to receive and convey the charge be in the path they are dashed aside; men and beasts are killed by the shock, trees and other less perfect conductors are scattered in fragments. Usually the more prominent objects as masts of ships, trees, and buildings are struck in the lightning’s course from the cloud, but occasionally those lowest down, near trees, and even in cellars receive the shock. In these cases the current is probably from the earth, whose electric condition is negative with respect to the clouds that pass over it. In either case the opposite electricities that strongly attract each other, and whose concurrence produces the destructive discharge near the earth’s surface are held apart by the stratum of air between them. When the attraction becomes too strong to be resisted by the insulating medium they rush together, in their fiery embrace, the flash and concussion being in proportion to the intensity of the charge. Do lightning rods protect? Yes; but not perfectly. If properly constructed, and of sufficient conducting capacity, they are a source of safety, and to discard them as useless is not wise.