摘要:

This paper describes the split‐telescope astrolabe and the pendulum‐astrolabe, which the author invented and assisted in bringing into use for the determination of astronomical longitudes and latitudes from observations of stars whose positions relative to other stars are determined on other instruments, and describes the system of the prospective constant‐altitude transit‐circle for further use of the principles of these instruments in the fields of geodesy and fundamental astronomy, including the determination of the spherical coordinates of all celestial objects. The most useful form of the constant‐altitude transit‐circle is expected to be an observatory instrument of about 15 inches aperture for the direct determination of much more accurate spherical coordinates of stars and other objects down to about the 11th or 12th magnitude, along with the latitude, longitude, and azimuth at the observatory. These more accurate star‐coordinates are expected to contribute fundamentally to the solutions of many problems of practical and theoretical interest. It is judged that there should be one or more constant‐altitude transit‐circles in each hemisphere, north and south, and that there should be about 15 photographic zenith‐tubes distributed throughout the world in addition to the one at the Naval Observatory in Washington, which has been the best standard of time and frequency and the best base station for the determination of longitudes since 1934. An Indefinite number of field‐instruments, probably pendulum‐astrolabes or photographic zenith‐tubes, are needed for determining astronomical longitudes and latitudes to be used in conjunction with geodetic observations for determini

ISSN:0002-8606    

DOI:10.1029/TR027i001p00001

年代:1946

数据来源: WILEY

ISSN:0002-8606    

DOI:10.1029/TR027i001p00008

年代:1946

数据来源: WILEY

摘要:

The usual procedure for determining the number of condition‐equations in the adjustment of a triangulation‐net is to build up the figure point by point. This method will give the number of angle and side equations, then azimuth, length, latitude, and longitude equations are added to obtain the total number [see 1 of “References” at end of paper”.In a complicated net, it is advisable to have a check on the total number of equations involved. The total number is given by the formula N = V − 3Sn+ Suin which N is the total number of equations, V is the total number of observed directions excluding those on lines fixed by previous adjustment, Snis the total number of new stations, and Suis the total number of unoccupied new stations. This formula is based on the fact that two lines determine a new point and each additional line to this point from established points adds, two equations if the line is observed in both directions or one equation if the line is observed in on

ISSN:0002-8606    

DOI:10.1029/TR027i001p00009

年代:1946

数据来源: WILEY

摘要:

A series of experiments was carried out at Saint Louis using the Macelwane‐Sprengnether horizontal component electromagnetic seismometers working in synchronism with type H‐S, L and N galvanometers having a period of twenty seconds; both the seismometer and the galvanometer were critically damped. With this equipment some more or less regular long period disturbances were recorded. These disturbances were finally eliminated by operating the seismographs in a seismic vault in which both the temperature and the humidity were controlled. While no physical explanation for this can be given at the present time, it appears worth while to point out that these results are similar to those found by Milne in Tokyo, the United States Coast and Geodetic Survey in Honolulu, and by Shaw in Engl

ISSN:0002-8606    

DOI:10.1029/TR027i001p00011

年代:1946

数据来源: WILEY

ISSN:0002-8606    

DOI:10.1029/TR027i001p00014

年代:1946

数据来源: WILEY

摘要:

H. O. WOOD [see 1 of “References” at end of paper] gives 1844 as the date of the inauguration of the Manila Observatory. This may be merely a misprint, but it is 21 years too early. Elsewhere [2]he gives 1884. (Doubtless this date relates to subsidizing by the Spanish Government as stated later in this paper.—Editor) The Manila Observatory originated with a series of meteorological observations which were commenced on January 1, 1865.In the Observatory Reports of 1868 there is mention of the record of an earthquake by the horizontal seismoscope, and hence the installation of this pendulum was made in the period 1865–1868; the exact date was not recorded. I say “there is mention in the report of 1868;” it would probably be more accurate to say that “there was mention,” for I doubt if any of those reports are still in existence in any part of the world; they no longer exist in Manila. This seismoscope was a simple pendulum having a 15‐inch suspension, carrying a point in the lower surface of the bob, and the point traced its motion in lycopodium powder sprinkled on a glass plate of spherical shape. There was also a vertical seismoscope consisting of a long spiral spring terminating in a bob which pushed an indicator down a scale to show the amount of vertical motion. In the Observatory we had a trace of the mark made by the horizontal seismoscope in an earthquake of 1872, the oldest record in the Observatory. However, this was not the first pendulum in the Philippines. A very complete report was issued by the Spanish Government on an earthquake of 1851, and mention is made therein of a pendulum in operation in a town in southern Luzon, and the amplitudes of its oscill

ISSN:0002-8606    

DOI:10.1029/TR027i001p00015

年代:1946

数据来源: WILEY

摘要:

Barometric lows over large bodies of water produce the maximum microseisms which decrease with increase in distance from the storm area. Tropical hurricanes, as well as winter storms, may be roughly traced by changes in amplitudes as the storms approach the stations in their paths. Geological units seem to have considerable influence on microseismic amplitudes. Local barometric pressure changes have no influence on the microseisms of nearby stations. Storms over land which seldom have deep lows do not produce appreciable microseisms on ordinary teleseismic records. Although such records yield valuable information on microseisms, they are not adequate for a complete study of these phenomena.

ISSN:0002-8606    

DOI:10.1029/TR027i001p00019

年代:1946

数据来源: WILEY

摘要:

The parallel growth of weather information for the special benefit of aviation and the use of punched‐cards in climatology is discussed, with the notation that very little use, in a climatological sense, had been made of the weather data designed for aviation until the beginning of World War II. The various types of climatic summaries in common use are described, and it is noted that they are not particularly well adapted to airways weather information, such as ceilings and visibility. By the use of punched‐card methods of machine tabulation, special and more complex types of climatic summaries are available. The use of duration frequencies of the limiting categories of airways weather data is considered to more closely approximate the operational needs of aviation and other interests than any other type of summ

ISSN:0002-8606    

DOI:10.1029/TR027i001p00027

年代:1946

数据来源: WILEY

摘要:

The diurnal variation of predisposition for precipitation strengthens and weakens frontal effects periodically and gives rise to a diurnal variation of precipitation. The predisposition is an effect of stability conditions In the atmosphere. Blue Hill Meteorological Observatory, near Boston, Massachusetts, is taken as a station characteristic of the coast, and Jasper, New York, 332 miles west of Blue Hill, is taken to represent inland conditions. Hourly frequencies of rainfall are taken from four years of record. The discussion singles out frequencies of slight (<0.05 in/hour) and heavy (≥0.10 in/hour) rainfall intensities. In winter a whole‐day wave predominates for both heavy and slight rainfall intensity, but heavy rainfall, inland, shows a rather well developed semidiurnal wave superposed. In summer, semidiurnal waves predominate both at the inland and the coast stations for the two intensities of rain. Numerical tables and diagrams facilitate understanding and provide rapid reference. Apparently instability showers prevail at the coast station, and cyclonic precipitation prevails at the inland station. In summer, at the coast station, a morning maximum of both heavy and slight precipitation‐intensity frequency exists, caused by instability showers while an afternoon or evening maximum is of convectional nature (semidiurnal wave). Probabilities are important to the forecaster. For example, the average probability of a heavy snowfall at the coast station during night is 4.3 times as great as in da

ISSN:0002-8606    

DOI:10.1029/TR027i001p00035

年代:1946

数据来源: WILEY

摘要:

It is pointed out that in order to evaluate the moisture‐factor in climate, the moisture supply or the precipitation must be compared with the water‐needs or the potential evapotranspiration, The distribution of precipitation through the year never coincides with, and seldom parallels, the distribution of potential evapotranspiration. When the precipitation is in excess of the need, the surplus goes to recharge ground‐water and produce runoff. When the precipitation does not equal the need, there is a deficiency which results in drought. Data on precipitation and potential evapotranspiration are presented for sixteen stations in the United States and tropical A

ISSN:0002-8606    

DOI:10.1029/TR027i001p00041

年代:1946

数据来源: WILEY