Abstract
M. HERMITE believes that the facts of geology admit of much simpler theoretical explanations than they have hitherto received. Whether his substitutes will be generally adopted is, we think, open to question; but as it would be a lengthy business to criticise them in detail we must restrict ourselves to a brief outline of their leading features. Mountain-making is not, as is generally thought, the result of a cooling of the liquid earth's interior, for that is not in accord with the theory of heat. It is caused thus:—The crust is very flexible. Materials deposited upon it produce a downward movement in that part with a corresponding upward one in another, so the ocean basins are constantly sinking and the continents rising. This upward movement is concentrated on the periphery of the basins, where the strata are bent, strained, and finally fractured. Motion is converted into heat and the temperature of this zone is elevated. It then communicates heat to the adjacent ocean, and thus increases evaporation. That results in a heavier rainfall. The precipitated water works down into the rising land, thus cooling it, and producing of course the greatest effect nearest to the surface. So the rise of temperature observed in sinking wells, &c., is due to a local cooling rather than to the cause usually assigned. That the consequence of mountain- making is abundant rain is proved by the prevalence of sandy deposits in the earliest geological ages. Another consequence is that periods of extensive and rapid deposit of detritus are succeeded by others of slow and regular sedimentation. M. Hermite passes on to explain the occurrence of the warm era with which the earth's history began, and the glacial epoch of its later days. Crust cohesion, he says, was great in early times, so more material was needed to make it sink; and thus the rise of temperature of the basins was greater. Evaporation was thereby increased and the whole surface covered with a veil of mist, resulting in a mild, uniform climate. But the heavy rains penetrating into the crust ultimately chilled it, and the streams which they produced cooled the ocean, till things returned to their former condition. As the cohesion afterwards became gradually less, this universal, warm, damp atmosphere did not recur, and the loss of heat by radiation gave rise to the seasons. But earth movements were augmented about the time of the passage of the Tertiary into the Quaternary, and led to precipitation which supplied the snow for the great glaciers. Thus this epoch was brought to an end rather by the diminished warmth of the ocean waters than by a rise of the general air temperature. At the present day the great glaciers of the Polar regions are largely fed by the water emitted from volcanoes. The Carboniferous period seems to have been a turning point in the history of the globe; for the crust up to that time was less fissured, and so was not chilled by the penetrating water; hence the high temperature of the seas kept the carbonic acid in the atmosphere. But after that became fixed in the form of coal the present conditions became possible. M. Hermite, we think, is not likely to get his theory adopted by geologists until he shows in more detail that it will harmonise with the facts; for he usually contents himself with vague statements, which read like his impressions of books. Also, when he plays havoc with the names of fossils (e.g., Rhinocéros, Thycorinus, for R. Tickorhinus), and attributes the cirques and gorges of mountain regions, with the cañons of more level districts, to the action of subterranean water, we feel that he is making a possible exception a general rule, and we cannot help doubting whether he has any practical knowledge of the science. In fact, much of his geology seems on a par with his statement (p. 29) that the volume of a series of spherical shells increases as the cube of their radii.
Essai d'une Explication par les Causes actuelles de la Partie théorique de la Géologie.
Par H. Hermite. Pp. 115. (Neuchâtel: Attinger, 1901.)
Article PDF
Rights and permissions
About this article
Cite this article
Essai d'une Explication par les Causes actuelles de la Partie théorique de la Géologie . Nature 64, 575 (1901). https://doi.org/10.1038/064575a0
Issue Date:
DOI: https://doi.org/10.1038/064575a0