摘要:

The first‐order control system of the United States established by the Coast an Geodetic Surrey forms a very extensive unified framework for the country. There are already in existence some 40,000 miles of arcs of triangulation covering the country and cutting it up into a more or less regular checker‐board arrangement. Plans have been made for a rapid extension of this control so as to place any point within easy reach of stations that can be used for local cont

ISSN:0002-8606    

DOI:10.1029/TR015i001p00036

年代:1934

数据来源: WILEY

摘要:

At the annual meeting of the American Geophysical Union in 1932 I reported on a tests made on the Bureau of Standards circular dividing‐engine which demonstrated th high accuracy of that instrument. I am now prepared to give some results of a series of circles graduated on this engine for the United States Coast and Geodetic Survey.These circles, intended for use in the 9‐inch Parkhurst first‐order theodolite, have been made of cast sterling silver. The choice of material was made by the United states Coast and Geodetic Survey. These circles are now being made under an arrangement whereby the entire task from the casting of the silver to the completion of the graduated circle is carried out at this B

ISSN:0002-8606    

DOI:10.1029/TR015i001p00038

年代:1934

数据来源: WILEY

摘要:

One who examines a map of the opposite coasts of the South Atlantic Ocean will struck at the similarity of the shapes of the coast‐line. Each major indentation on the east coast of South America has a corresponding protuberance on the west coast of Africa. If one were to take a compass and make measurements on a globe it would be found that dimensions agree closely.A study of this phenomenon has brought about a new conception of the nature of the Earth's crust and movements or drifts of land‐masses. This new conception is called the theory of displacement of continents or sometimes referred to as the displacement‐t

ISSN:0002-8606    

DOI:10.1029/TR015i001p00040

年代:1934

数据来源: WILEY

摘要:

Almost three centuries and a quarter have passed since the first ship entered Hudson Bay on its voyage of discovery. Sailing southward from the Straits, its intrepid master, Henry Hudson, commenced the exploration of Canada's great inland sea. In the succeeding months he searched both James and Hudson bays for a navigation‐route leading to the “Western Sea,” compiling as he went a rough sketch‐map showing the general form of the Bay, together with the location of one or two of the principal island

ISSN:0002-8606    

DOI:10.1029/TR015i001p00041

年代:1934

数据来源: WILEY

摘要:

There has now been completed a set of measurements ofgwith each of our four silca pendulums, all resting by planes of stellite upon the same agate knife‐edge. The results follow:Pendulum Relative flexibility Mass ingAverage departurenumber kg from mean1 1.00 1.1 980.082 0.0172 0.89 1.9 980.085 0.0113 0.64 3.6 980.068 0.0074 0.31 3.6 980.077 0.006It is of interest to notice the greater precision of the results with the heavier pendulums. This is to be expected, as the more massive pendulums should be less affected by trifling disturbance

ISSN:0002-8606    

DOI:10.1029/TR015i001p00045

年代:1934

数据来源: WILEY

摘要:

Possible detection of the influence of the Moon on observed clock‐corrections has been examined by tabulating according to hour‐angle and declination of the Moon the differences of two definitive clock‐corrections taken on the average of eight hours apart on the same night. These observations were taken on the 9‐inch transit circle at the United States Naval Observatory on 1,535 nights in the interval 1903–1921. The corrections were run together with definitive 24‐hour rates and the differences formed as given in Table 1. The differences were grouped every three hours for hour‐angle of the Moon at midnight, and for declinations of the Moon +28° to +15°, +15° to −15°

ISSN:0002-8606    

DOI:10.1029/TR015i001p00046

年代:1934

数据来源: WILEY

摘要:

The Coast and Geodetic Survey produces the bulk of the geodetic work in this country. This work consists of triangulation and leveling for furnishing the horizontal and vertical control‐nets, astronomical observations, base‐measurements, gravity‐determinations, and the operation of two international latitude‐observatories. All except gravity and the variation‐of‐latitude work may be classed as a fundamental part of the triangulation a

ISSN:0002-8606    

DOI:10.1029/TR015i001p00048

年代:1934

数据来源: WILEY

摘要:

The second year of use of the Brown gravity‐apparatus has been fully as successful as the first year. Since the previous meeting of this Section about 110 stations have been determined, in a working time of eight months or less. The other four months of the year were devoted by the party to astronomical observations and other geodetic work.A year ago gravity‐work was in progress in Cuba. A total of 79 determinations were made on the Island by the observer, Lieutenant A. J. Hoskinson, during the season. The work was done in cooperation with the Atlantic Refining Company of Cuba, who paid all expenses except the salaries of the observer and his assistant. The instruments and gravity‐truck were furnished by the Coast and Geodetic Survey. Dr. Roy E. Dickerson, Chief Geologist of the Atlantic Refining Company, selected the locations of the stations, and gave very valuable assistance to the party in many

ISSN:0002-8606    

DOI:10.1029/TR015i001p00053

年代:1934

数据来源: WILEY

摘要:

An annual taking of stock of seismological progress is a useful procedure since it is both instructive and stimulating. In a subject with so many subdivisions covering a wide range of activity it is by no means easy for any one person to cover the field. The writer has volunteered to do this because his official duty requires him to keep in touch with all branches of seismological effort in order that the work of in the Coast and Geodetic Survey in this field may be coordinated with other activities. In previous reports it has been customary to list each organization with a statement of accomplishment of each. In the present report the alternate plan is followed of listing the activities and referring under each to the appropriate organizations. To following review of activity must not be considered exhaustive. There are probably omissions of activities that are as important as those included. If such omissions are noted, information regarding them will be welcomed.

ISSN:0002-8606    

DOI:10.1029/TR015i001p00058

年代:1934

数据来源: WILEY

摘要:

The work of the Jesuit Seismological Association, which is a voluntary organization of seismological stations which are owned and operated by the Jesuit universities and colleges in the United States, was somewhat curtailed during the year 1933 because of economic conditions. The following stations retained their membership: Buffalo, Chicago, Cincinnati, Denver, Fordham, Georgetown, New Orleans, Santa Clara, Spokane, Weston, and the Central Station at Saint Louis. The Central Station is associated with the Department of Geophysics of Saint Louis University and consequently with the stations at Florissant and Saint Louis and with the cooperative station at Little Rock, Arkansas.

ISSN:0002-8606    

DOI:10.1029/TR015i001p00062

年代:1934

数据来源: WILEY