Page:Popular Science Monthly Volume 21.djvu/584

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and petroleum-bearing. A kind of scum of petroleum may be seen on the edges of the craters of Macaluba. The gases escaping from them contain from thirty-four to thirty-six per cent of carburetted hydrogen, with sulphuretted hydrogen and carbonic acid. The soil around Paterno, in which the center of the second eruption is situated, is calcareous, and abounds in springs containing carbonic acid. The waters, infiltrating the soil, raise its temperature and form a kind of veined alabaster, which is much esteemed. The eruptions are occasioned by the passage of carburetted hydrogen, which is formed by the decomposition of organic matters within the earth, in seeking its way to the surface through beds of clay which have been washed down into the crevices. Mud-volcanoes of another kind, of which those of New Zealand and Iceland afford examples, are formed by vapors of water proceeding from ordinary volcanoes, and are distinguished by the high temperature of the mud and the absence of carburetted hydrogen.


The Oldest Flowering Plant.—MM. G. de Saporta and A. F. Marion have been studying the genera Williamsonia and Goniolina, the most ancient angiospermous plants of which the fructiferous organs have been preserved. The stem bears at its extremity reproductive apparatus in which two different modes of structure, indicating a dioecious plant, may be distinguished. A many-leaved involucre, having its bracts so curved as to give it a globular appearance, is observed in every case. The parts of the male involucre are disposed in a single row, connivent, elongated, and attenuated at the end. The organ represents a conical axis, the base of which is surrounded with a circular zone marked with radiating striæ. The outer edge of this zone, when it is exposed, is occupied with a collection of very small compartments of irregular hexagonal contour, that seem to represent as many pollen-boxes. This basilar zone corresponded with a sterile and persistent portion of the androphore, which in its integrity probably covered the whole conical receptacle with a matted layer of staminal appendages, recalling by their disposition and office the male organs of the Typhas. The female organs of the Williamsonia are provided with the globose involucre of the male flower, except that the bracts are a little shorter. The organ contained within this involucre, which was certainly caducous at maturity, consisted of a receptacle or spadix in the form of a more or less globose solid cushion. The central leaves of the involucre, which remain in place, testify by their thickness to a particularly tough primitive condition. The spadix in the midst of them is covered on its upper part with carpellary compartments, while the fibro-ligneous tissue which composed the axis of the receptacle is recognizable in the lower part.


French Exploring Expeditions.—Since 1874 the French Government has authorized the organization of three hundred and thirty scientific missions, of which one hundred and sixty-eight were to operate in Europe, fifty-four in Africa, forty-eight in Asia, thirty-six in America, and twenty-four in Oceania. Most of these missions are still at work, and generally report to a commission appointed by the Minister of Public Instruction. The "Revue Scientifique" reviews the condition of the most important of the missions, particularly of those which relate especially to geography. M. Lantz is in Madagascar, studying the natural history of the less accessible parts of the island; M. Pélagaud is exploring the Mascarene Islands; M. Montano, Malaysia; and M. Marché, the Philippine Islands. In Africa, M. Matheis is exploring the region between the Niger and the Bénoué; M. Revoil is examining the Somauli country from Cape Guardafui to the Strait of Bab-el-Mandeb; Messrs. Savorgnan de Brazza and Ballay are supplementing Stanley's work on the Congo; Messrs. Roux, Cagnat, and Gosselin are studying the geography and archaeology of Tunisia; M. Galliéni has concluded a treaty for the navigation of the Niger to Timbuctoo; and several expeditions are engaged in the eastern part of the continent. In Asia, M. Haas is pursuing artistic and historical investigations in Hindostan; M. Chantre has started from Bagdad to look into the anthropology and zoölogy of the region of the Caspian Sea and Mount Ararat; M. Clermont-Ganneau is engaged in archæological work in the east of