Page:Popular Science Monthly Volume 15.djvu/443

 where they cut lumber. The men are extremely ignorant, and one of their pastimes is this practice of tickling one another. When the jumpers are excited to strike or jump, or to perform any of their automatic acts, they present the appearance of entranced persons: their faces pale, eyes fixed and glassy, and limbs trembling. One of these jumpers is a waiter, and when told suddenly to "drop it," he at once lets fall whatever he may have in his hand. Another has so susceptible a stomach that he at once throws up his meal when anyone "gags" or makes the motion of vomiting in his presence. The man has grown thin, and at one time was almost starved. One man, standing on the bank of a pond with a five-dollar gold piece in his hand, was told to "throw it," and threw the money into the water. Another was standing near a kettle of fish; being told to "jump," he leaped into the kettle. In these acts the jumpers are absolute automatons, utterly without volition or responsibility: they are to be compared to persons afflicted with St. Vitus's dance, hysteria, or epilepsy. Performances of a somewhat similar character were, last winter, witnessed in a town of Vermont during a revival of religion. Here the victims of abnormal religious excitement would roll on the floor in most absurd and undignified attitudes, whence the appellation of "the holy rollers!"

New Process for the Protection of Iron Surfaces.—A new process for protecting iron from rust has been invented by M. Dodé. It consists in coating, either by means of a bath or a brush, any objects in cast or wrought iron (freed from the damp they may contain) with a composition of borate of lead, oxide of copper, and spirits of turpentine. This application soon dries on the surface of the iron, and the objects are then passed through a furnace, which is heated from 500° to 700° Fahr., according to the thickness of the articles under treatment, so as to bring them-to a cherry-red heat when passing through the center of the furnace. At this point the fusion of the metallic pigment takes place; it enters the pores of the iron, and becomes homogeneously adherent thereto, covering the objects with a dark coating, which is not liable to change under the action of the air, gases, alkaline or other vapors, nor to scale off from the surfaces to which it has been applied. When any considerable depth of "inoxidation" is desired, the object may be immersed in the composition for the time requisite to absorb a sufficient quantity of it. This process supersedes painting and varnishing, and iron objects thus heated are impervious to rust. The cost of application is about half a cent per superficial square foot.

The Mance Heliograph.—The Mance heliograph, an instrument for signaling by means of reflected solar rays, is now in use among the British forces in South Africa. The signals made by the Mance heliograph are visible, under favorable conditions of position and atmosphere, to very great distances, and have been read as far as eighty and a hundred miles. It consists of a specially prepared mirror, with mechanism for reflecting the sun's rays with absolute precision to any required spot, notwithstanding the sun's apparent motion. By pressure en a finger-key the flashes are made of short or long duration, thus adapting the instrument to the Morse code of telegraphy. A second mirror is provided to permit of signaling being carried on irrespective of the sun's position. The instrument intended for field service weighs from six to eight pounds, and is mounted on a light tripod stand. The working parts are protected from injury during transit, and the complete apparatus admits of being easily carried, as it is also efficiently worked, by one man.

Experiments in Opium-Smoking.—The Russian traveler, Dr. Miclucho Maclay, while recently on a visit to Hong-Kong, experimented on the effects upon himself of smoking opium. The experiment was made at the Chinese Club, and was under the direction of Dr. Clouth, who made the following notes: Mr. Maclay was in normal health, and had fasted eighteen hours before commencing the experiment. He had never smoked tobacco. Twenty-seven pipes, equivalent to 107 grains of the opium used by the Chinese, were smoked in two and three quarter hours at tolerably regular