摘要:

Geodesy is one of the oldest of the geophysical sciences. Originally it embraced only a limited field, consisting of the determination of the shape of the earth and its size and the means by which this was done. But now the subject of geodesy is very closely allied with other matters and there are few geophysical questions that do not, either directly or indirectly, concern the geodesist in the solution of his problems.Almost every country of the world that pretends to any standing has organized a service for the purpose of carrying on what are called geodetic surveys. As a matter of fact, any survey of the land in which the shape and size of the earth are taken into consideration can be called geodetic; thus, the hydrographic surveys along the coast made for a sailing chart are really geodetic surveys and, similarly, a topographic survey of a large area may be considered to be a geodetic survey; but what I have in mind in speaking of geodetic surveys, are triangulation, base measurements, precise leveling, etc.

ISSN:0002-8606    

DOI:10.1029/TR001i001p00545

年代:1920

数据来源: WILEY

摘要:

Although earthquakes have received sporadic attention for some time in the past, their systematic study may almost be said to have begun with Mallet about the middle of the last century; and it was only towards the end of the century that instruments delicate enough to register distinct shocks were developed, making it possible to gain some knowledge of the characteristics of earthquake vibrations and the velocities with which they are propagated through the earth. But, notwithstanding the shortness of the time during which these studies have been in progress, the science has been well outlined and first approximations to the solutions of many of its problems have been obtained. The time has now arrived for more concentrated and still more systematic attacks, from which important results may be confidently expected.

ISSN:0002-8606    

DOI:10.1029/TR001i001p00555

年代:1920

数据来源: WILEY

摘要:

Meteorology is one of those sciences which developed on the side of practical application for the welfare of mankind to a far greater extent than the development on the scientific or pure theory side of the problem. As a result, meteorologists responsible for the practical applications to human welfare are at a distinct disadvantage on account of the imperfect and incomplete theoretical development of the science.The United States was distinctly the pioneer among all nations in officially and formally creating a meteorological service. This was done by a joint resolution of Congress in 1870, which provided that advices, warnings and forecasts concerning future weather conditions should be prepared and issued for the benefit of agriculture, commerce and navigation.

ISSN:0002-8606    

DOI:10.1029/TR001i001p00561

年代:1920

数据来源: WILEY

摘要:

The early completion of the general magnetic survey of the globe, as undertaken by the Department of Terrestrial Magnetism of the Carnegie Institution of Washington and cooperating countries, will afford the necessary data for the investigation of some of the so‐called “greater problems of the earth's magnetism.” One of these is the determination of the various systems of magnetic and electric forces which together make up the total terrestrial magnetic field as observed at the earth's surface. It is known from previous analyses that the earth's magnetic field consists of an internal system of forces, which constitutes by far the major portion; secondly, an external system, supposedly to be ascribed to electric currents circulating in the earth's atmosphere; and, thirdly, a system possibly such as that of vertical electric currents which pass from the atmosphere into the earth and vice versa. The definite settlement of the question as to the existence of the third system is regarded by Sir Arthur Schuster as one of the chief outstanding problems in terrestrial magnetism. This problem involves the question whether or not the magnetic forces of the earth can be entirely referred to a potential. If not, then the question arises as to the existence of vertical electric currents, which will be of interest both to students of the earth's magnetism and of the earth's electricity, using the latter term in its most general sense so as to include electric phenomena arising from systems both below and above the earth's surface. The ocean work of the Department of Terrestrial Magnetism has been arranged with the special view of obtaining the requisite data for the solution of this interesting question. But for the war all the necessary data and the results of their discussion would be availabl

ISSN:0002-8606    

DOI:10.1029/TR001i001p00572

年代:1920

数据来源: WILEY

摘要:

The former and present function of the ocean in the history of the earth and in its economy has forged bonds of kinship between oceanography and many other branches of science. Ever since the ocean became the world‐encompassing highway of communication, its surface aspects, embracing the movements of the waters in waves, tides, and currents, have been subjects of observation. With the advance of the physical sciences and a knowledge of the extent of the ocean came the realization that so large an expanse of a substance having the highest known capacity for heat must, to a large extent, govern the external temperature of the earth and exercise an important influence as a factor in geophysics. But centuries of voyaging did not extend marine observations beyond the delineation of coasts and the service of navigation; and, in the middle of the nineteenth century, the sea remained unfathomed, and the observations of the physicist, the chemist, the geologist, and the biologist did not extend beyond the shallow coastal water

ISSN:0002-8606    

DOI:10.1029/TR001i001p00580

年代:1920

数据来源: WILEY

摘要:

Of the various sciences represented in the American Geophysical Union that of volcanology is perhaps the most complex and has probably most points of contact with the other geophysical sciences. This complexity and variety in the problems presented by the study of volcanoes arises, in part, from the fact that they are, as has been well said, “natural laboratories.” Also the distribution and many of the activities of volcanoes are closely connected with some of the physical, as well as the chemical forces that are involved in the formation and in the present condition of the earth.In presenting some of the main problems of volcanology, we may begin with those that are essentially and more purely volcanological, and then take up seriatim the consideration of certain problems in which the other sciences represented by sections of the Union may enter. Because of the limitation of space only a brief enumeration and presentation will be made, and no adequate discussion will be undertaken. I am much indebted to various members of the Union for some valuable suggestions, which will be mentioned in their proper pla

ISSN:0002-8606    

DOI:10.1029/TR001i001p00583

年代:1920

数据来源: WILEY

摘要:

The subject‐matter of geophysical‐chemistry may be defined as “the physical properties and chemical reactions of the substances and aggregates that make up the earth”. It may therefore be roughly divided into two parts: A. Properties and reactions of materials accessible at the earth's surface. B. Properties and reactions of materials in the earth's interior.Each of these may again be sub‐divided as follows:1. Properties and reactions of individual chemical substances; for example, the silicate minerals.2. Properties and reactions of aggregates; for example, oceanic water, silicate rocks.3. Properties and reactions of larger units of matter; for example, glaciers, b

ISSN:0002-8606    

DOI:10.1029/TR001i001p00592

年代:1920

数据来源: WILEY