dangerous to ships that happen to come within their influence.
That they are caused by electricity has been proved by experiment—miniature waterspouts have been produced by artificial means; and as Dr. Bonzano of New York gives particular directions how the thing ought to be done, we quote his words for the benefit of those who happen to possess electrical machines:—
"From the conductor of an electrical machine suspend, by a wire or chain, a small metallic ball (one of wood covered with tinfoil); and under the ball place a rather wide metallic basin, containing some oil of turpentine, at the distance of about three-quarters of an inch. If the handle of the machine be now turned slowly, the liquid in the basin will begin to move in different directions and form whirlpools. As the electricity on the conductor accumulates, the troubled liquid will elevate itself in the centre, and at last become attached to the ball. Draw off the electricity from the conductor, to let the liquid resume its position; a portion of the turpentine remains attached to the ball. Turn the handle again very slowly, and observe now the few drops adhering to the ball assume a conical shape, with the apex downward; while the liquid under it assumes also a conical shape, the apex upward, until both meet. As the liquid does not accumulate on the ball, there must necessarily be as great a current downward as upward, giving
