Page:Popular Science Monthly Volume 14.djvu/854

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834
THE POPULAR SCIENCE MONTHLY.

ing great crevices. At some former time a large segment was cut from the base of this column. Starting from one of these crevices, an excavation was made, cutting a mass from the base having an arc of thirty feet, and making a cavity in the pillar itself ten feet wide, seven feet high, and five feet deep. This excavation has hitherto been regarded as a deliberate attempt of the miners to fell the column, but Mr. Hovey thinks the work must have been done a thousand years ago.

 

Commercial Products of New Caledonia.—M. Jules Gamier, who has spent three years in New Caledonia investigating its mineral resources, states that all the principal vegetable productions of the tropics grow well on that island, though, with the exception of coffee and tobacco, they are subject to periodical destruction by invasions of grasshoppers. Cotton, moreover, is liable to damage during the rainy season, which, coinciding with the gathering of the crop, destroys the produce. There are several native oil-yielding plants, and the culture of the mulberry and silkworm have been introduced with success. The forests contain many useful timber-trees; but the most active industry is the raising of cattle, in which an active export trade is carried on with Australia. Of other animal products there is nothing of commercial value except the fish, which are abundant and of great variety. The chief source of wealth in the island is, however, its metallic products. It is rich in gold, copper, and nickel, the latter presenting itself in the form of a magnesian hydro-silicate, called by Professor Dana Garnierite. The native inhabitants number thirty-five thousand, and the whites seventeen thousand. The recent insurrection will not interfere with the progress of the colony.

 

Professor A. Agassiz's Zoological Laboratory.—Professor Alexander Agassiz's zoological laboratory at Newport is admirably contrived to accommodate a small number of workers. It is forty-five by twenty-five feet. The whole of the northern side of the floor, upon which the work-tables and microscope-stands are placed, is supported on brick piers and arches independent of the brick walls of the building. The rest of the floor is supported entirely on the outside walls and on columns on the north side. This gives to the microscopic work the great advantage of complete isolation from all disturbance caused by persons walking over the floor. The material for the laboratory procurable at Newport is abundant. The dredging is fair and not difficult, as the depth in the immediate neighborhood does not exceed twenty to thirty fathoms. The pelagic fauna, however, is the most abundant. During the course of each summer, by the use of the dip-net, representatives of all the more interesting marine forms can be found. The laboratory stands on a point at the entrance of Newport Harbor, past which sweeps the body of water brought by each tide into Narragansett Bay, and carrying with it everything which the prevailing southwesterly wind drives before it. Newport Island and the neighboring shores form the only rocky district in the long stretch of sandy beaches extending southward from Cape Cod—an oasis, as it were, for the abundant development of marine life along its shores.

 

Making Sound-Vibrations visible.—A very ingenious method of recording articulate vibrations by means of photography has just been invented. The apparatus (says "Galignani's Messenger") consists of a steel mirror capable of oscillations on a diametral axis, to the back of which is attached a lever connecting it with the center of a telephone-disk arranged with an ordinary mouthpiece. Whenever the disk is made to vibrate, the mirror oscillates with it, and a beam of sunlight thrown on the reflector from a heliostat describes lines of light on a suitably prepared screen. If the latter be movable at right angles to those lines of light, and carries a collodion film, the oscillation of the light is recorded on the prepared surface as a more or less complex curve having the peculiarity of the sound-wave which caused each particular motion. Another and simpler phoneidoscope is suggested by a writer in "Nature": it may be made without the aid of any apparatus whatever, by bending the forefinger and thumb of one hand so as to form a circle, and then with the other hand draw-