Page:Popular Science Monthly Volume 25.djvu/878

860 only through valleys occupied by large streams. The first attack was made upon Dunnagiri, which is 23,184 feet high. In order to reach it they had to climb over two peaks 17,000 and 18,000 feet high, and then, after a five days' march, they camped on a glacier at the height of 18,400 feet. On the sixth day they reached a height of 22,500 feet, when, a snow-storm coming on, they were compelled to retreat, after they had come in sight of their goal. Mr. Graham observes that the peaks of the Himalayas, as a rule, are considerably steeper than those of the Alps; and he is convinced that breathing is no more difficult at the height he reached than at 10,000 feet lower down. The party also ascended the Kang La, 20,300 or 20,800 feet high, and a new mountain, 23,326 feet high, which was called Mount Monal, from the number of birds of that name seen upon its slopes.

Volcanic and Cosmic Dusts in Submarine Deposits.—Messrs. John Murray and A. Renard have taken advantage of the phenomena attending the eruption of Krakatoa last year for the extension of their studies in the accumulation of volcanic débris and cosmic dust in deep-sea deposits. Mr. Murray had already shown, before the Royal Society of Edinburgh, in 1876, that volcanic materials play the most important part in the formation of these deposits, and how they may have been furnished by the decomposition of pumice and the settling of incoherent volcanic ejections. Rounded fragments of pumice are collected on the surface of the sea in regions far from coasts, and at certain points on the bottom of the ocean the greater part of the deposit is composed of vitreous splinters derived from the trituration of such stones. The eruption of Krakatoa in a few hours filled the Bay of Lampong with about 150,000,000 cubic metres of ejected matter. Floating fragments from this source were collected on the surface of the water with their angles rounded off, and showing, as the only asperities upon their surface, crystals and fragments of crystals projecting beyond the mass of vitreous matter. The crystalline fragments and volcanic minerals can not be identified with certainty when reduced to their finest state, as in the deep-sea deposits; for in that condition they lose all their characteristics of form and optical properties. The case is different with the vitreous particles derived from the pumice, or included in the volcanic ash, whose characters remain constant to the extreme limits of pulverization. The results of the study of the micro-structure of the vitreous particles from Krakatoa, which are described in full by the authors, can be applied with most perfect exactitude to the volcanic dusts, which have been determined as such, in the deep-sea deposits. The latter have, however, only partly been derived from the pulverized ejections of a volcano, but more from the trituration of floating pumice; but it is hardly possible to trace the differences between the two. The minerals that can be determined in the ashes of Krakatoa are the same as are almost always found in the deposits along with the splinters of glass. It is not to be expected that the volcanic dusts found in all the deep-sea deposits shall be uniformly identical. In the first place, they may originate from magmas of varying characters, according as they come from volcanoes in different parts of the world. The matter also goes through a sifting process as it is carried through the air and in settling in the water. The vitreous particles, being lighter, are carried farthest from the volcanic center, and are longest in reaching the bottom. The fact has been illustrated in the case of Krakatoa that, in proportion as the ashes are collected at a greater distance from the volcano, they are less rich in minerals, and the quantity of vitreous matter predominates; a submarine tufa-deposit in the center of the South Pacific, in which the particles are graduated from the bottom up, illustrates the difference in the facility of settling. The evidence that has been adduced in favor of the hypothesis of a circulation in the atmosphere and a settling upon the earth of cosmic dusts is doubted by some, who have suggested various possibilities of an earthly origin for the particles described as cosmic. According to our authors, however, many of the doubts are at once removed by a statement of the circumstances under which cosmic spherules are formed in deep-sea deposits, and when the association of the metallic spherules with the most characteristic bodies of undoubted meteorites is shown. Cosmic particles are found in most