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THE POPULAR SCIENCE MONTHLY.

blocks, when M. Rathelot hit upon the following method of operation: In the first place, he cut off the back of the book so as to leave nothing but a mass of leaves, which the fire had caused to adhere to each other. He then steeped the book in water, and afterward exposed it, all wet as it was, to the heat at the mouth of a calorifère; the water, as it evaporated, raised the leaves, one by one, and they could be separated, but with extraordinary precautions. Each sheet was then deciphered, and the copy certified by a legal officer. In this way the records of nearly 70,000 official acts have been saved. The appearance of the pages was very curious—the writing appeared of a dull black, while the paper was of a lustrous black, something like velvet decorations on a black-satin ground, so that the entries were not difficult to read.

 

Sonorous Sand.—There was recently presented to the California Academy of Sciences, by W. R. Frink, of Honolulu, a specimen of "sonorous sand" from the island of Kauai, one of the Hawaiian group. In a letter accompanying the specimen, Mr. Frink states that the bank from which this sand was taken commences at a perpendicular bluff at the southwest end of the island, and extends a mile and a half almost due south, parallel with the beach, which is about 100 yards distant from the sandbank. The latter is about sixty feet high, and is constantly extending to the south. At the extreme south end, and for half a mile north, if you slap two handfuls of the sand together, a sound is produced like the hooting of an owl. If a person kneels on the steep incline, and then, with the two hands extended and grasping as much sand as possible, slides rapidly down, carrying all the sand he can, the sound accumulates till it is like distant thunder. "But the greatest sound we produced," says Mr. Frink, "was by having one native lie upon his belly, and another take him by the feet and drag him rapidly down the incline. With this experiment the sound was terrific, and could have been heard many hundred yards away."

The sand of Jebel Nagus, a hill lying to the west of the mountain usually called Sinai, in Arabia, possesses similar properties. According to Captain H. S. Palmer, an English traveler, it gives out musical sounds whenever it is set in motion. The sound produced "is neither metallic nor vibratory. It might be compared to the sharpest notes of the Æolian harp, or to the sound caused by forcibly drawing a cork over wet glass. When at the maximum intensity it may be heard at a considerable distance."

Dr. James Blake, of the California Academy of Sciences, has investigated with the microscope the structure of the Kauai sand, and states that the grains are chiefly composed of small portions of coral, and apparently calcareous sponges. They are all more or less perforated with small holes, mostly terminating in blind cavities, which are frequently enlarged in the interior, communicating with the surface by a small opening. The structure of the grains, Dr. Blake thinks, fully explains the reason why sounds are emitted when they are set in motion. The mutual friction causes vibrations in their substance, and consequently in the sides of the cavities; and, these vibrations being communicated to the air in the cavities, the result is sound. There are, in fact, millions upon millions of resonant cavities, each giving out a sound which may well acquire a great volume, and even resemble a peal of thunder. The sand must be dry, however, in order to produce sound; for, when the cavities are filled with water, the grains are incapable of originating vibrations.

 

Prof. Wurtz on the Order of Nature.—Prof. Ad. Wurtz, in his address as President of the French Association, referred as follows to the ultimate questions of science: "With regard to matter, it is ever and everywhere the same, and the hydrogen of our earth's water we trace in our sun, in Sirius, and in those nebulae which are still unformed worlds. Everywhere is motion, too; and motion, which appears inseparable from atoms which constitute matter, is the origin of all physical and chemical force. Such is the order of Nature; and the deeper Science searches into her mysteries, the more clearly it evolves the simplicity of the means used, and the infinite diversity of results. Thus, from under the edge of the