bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Swedish magnetic‐survey boat Kompass
Authors: Ljungdahl Gustaf S. 
Published: February 2008

During the spring of 1938, the Hydrographic Survey of Sweden (Kungl. Sjökarteverket) launched a small vessel, named Kompass, mainly intended for magnetic measurements in the waters surrounding Sweden. She was built at a shipyard, generally engaged in building wooden motor‐boats for use of fishermen at sea. Her construction and dimensions differ but slightly from the common type of such boats.Her length is 17.0 meters, beam 5.4 meters, and displacement 50 tons. She makes 7.5 knots driven by a twin‐cylinder crude‐oil engine of 60 horse‐power. The small sails are intended mainly for emergency and to reduce movements when in heavy seas.
The ionosphere at Huancayo, Peru, October, November, and December, 1938
Authors: Wells H. W. , Stanton H. E. 
Published: February 2008

This report on ionospheric conditions is in continuation of those published in preceding issues of this Journal submitting results of continuous multifrequency ionospheric recordings at the Huancayo Magnetic Observatory, Department of Terrestrial Magnetism, Carnegie Institution of Washington. The current data for the quarter October to December, 1938, are obtained from recordings for each hour of the day and for every day of the month except for short intervals necessary for maintenance of the equipment.Table 1 contains mean hourly values of virtual height, critical frequency, and lowest frequency received, for the last quarter of 1938. Figure 1 presents the data of Table 1 in graphical form. The following general discussion of characteristics is pertinent: (1) F‐region—Virtual heights during the daylight hours show little difference for October and November. Daytime heights for December were generally greater than for the preceding two months. The maximum heights for each month were recorded during the post‐sunset “hump.” The average maximum amplitudes for October and November are about the same but the amplitude of the December peak is somewhat less than the others. Also notable is the fact that the crests occurred at 19h, 20h, and 21h for October, November, and December, respectively.
Provisional solar and magnetic character‐figures, Mount Wilson Observatory January, February, and March, 1939
Authors: Mulders Elizabeth Sternberg , Nicholson Seth B. 
Published: February 2008

Twelve sunspot‐groups were observed on February 24, none very large or active. One of these was within 3° of the center of the solar disk when the storm of February 24 began.The storm of March 21–23 was probably due to the active group 57° west, 15° south. Several other groups were present on the Sun. The largest was at 25° east, 15° north. Two very small groups were directly in the center of the disk during the storm, one on March 22.4, and the other on March 23.4.
The influence of the surrounding air upon the time of vibration of a magnet
Authors: Veldkamp J. 
Published: February 2008

In 1935 a dissertation was published by A. Burger about the error in the time of vibration of a magnet, caused by air‐masses moving with it. A summary of the measurements was given by G. Fanselau in Zeitschrift für Geophysik (12, 58, 1936).As Lamont had already found, a vibrating magnet sets the surrounding air in motion. In order to determine the moment of inertia, the magnet is loaded with a bar of known inertia. From the times of vibration with and without the bar the moment of inertia of the magnet is calculated; the enveloping air‐masses moving with it, however, may cause an important error.
The ionosphere at Huancayo, Peru, January, February, and March, 1939
Authors: Wells H. W. , Stanton H. E. 
Published: February 2008

This report on ionospheric conditions is in continuation of those published in preceding issues of this JOURNAL submitting results of continuous multifrequency ionospheric recordings at the Huancayo Magnetic Observatory, Department of Terrestrial Magnetism, Carnegie Institution of Washington. The current data for the months January, February, and March, 1939, are obtained from recordings for each hour of the day and for every day of the month except for short intervals necessary for maintenance of the equipment.Table 1 contains mean hourly values of virtual height, critical frequency, and lowest frequency received, for the first quarter of 1939. Figure 1 presents the data of Table 1 in graphical form. The following general discussion of characteristics is pertinent:
The ionosphere Huancayo, Peru, April, May, and June, 1939
Authors: Wells H. W. 
Published: February 2008

This report on ionospheric conditions is in continuation of those published in preceding issues of this Journal1 submitting results of continuous multifrequency ionospheric recordings at the Huancayo Magnetic Observatory, Department of Terrestrial Magnetism, Carnegie Institution of Washington. The current data for the months April, May, and June, 1939, are obtained from recordings for each hour of the day and for every day of the month except for short intervals necessary for maintenance of the equipment.Table 1 contains mean hourly values of virtual height, critical frequency, and lowest frequency received, for the second quarter of 1939. Figure 1 presents the data of Table 1 in graphical form. The following general discussion of characteristics is pertinent:(1) F‐region—The downward trend of virtual heights during daylight hours which was remarked for February and March, 1939, in the preceding issue of this Journal was followed by an upward trend during this entire quarter. Maximum heights for each month were recorded during the characteristic post‐sunset hump which was most pronounced at 19 h, although for June the peak of evening heights exceeds the maximum daytime heights by only a few kilometers. The general trend of the evening peak‐values during this period is downward with a sharp drop during June. In general, these characteristics conform to the characteristic trends outlined for the year, 1938, in a summary of ionospheric data from Huancayo2 in which attention was called to the apparently anomalous conditions which show that maximum daytime heights at Huancayo are recorded around June and December, while maximum evening heights are recorded around March and September.
Sitka Magnetic Observatory October to December, 1939
Authors: Gebhardt Robert E. 
Published: February 2008

October 3–4—A small disturbance began gradually at about 08h 30m GMT, October 3, and increased slowly during the first five hours. The conditions continued mildly disturbed until 15 h, October 4. Ranges: D, 126′; H, 1053 gammas; Z, 760 gammas.October 6—A short period of disturbance occurred between 04h and 11h GMT, October 6. H increased steadily during the first period until 05h 30m, then suddenly decreased 450 gammas during the next ten minutes. Thereafter the traces gradually returned to normal. Ranges: D, 102′; H, 585 gammas; Z, 500 gammas.
Magnetic Observatory, Capetown July to September 1939
Authors: Ogg A. 
Published: February 2008

Note: D and Z are negative; changes are in the algebraic sense.July 3—A small storm began with a sudden commencement at 00h 40m GMT, July 3. At about 03h 55m bays developed in the three traces and also at about 18h 30m larger bays with peaks occurred. The ranges of the larger bays were ± 10′ in D, +42 gammas and −26 gammas in H, and the numerical value of Z decreased 56 gammas and increased 24 gammas. The storm ended at 24h.
Huancayo Magnetic Observatory January to March, 1940
Authors: Wells H. W. 
Published: February 2008

(Latitude 12° 02′.7 N., longitude 75° 20′.4 or 5h 01m.4 W. of Gr.)January 3—There was a sudden commencement at 14h 41m GMT, January 3, which was followed by generally disturbed conditions through 24h, January 3. Range: H, 625 gammas.
Watheroo Magnetic Observatory January to March, 1940
Authors: Parkinson W. C. 
Published: February 2008

(Latitude 30° 19′.1 S., longitude 115° 52′.6 or 7h 43m.5 E. of Gr.)January 3—A short disturbance of moderate intensity began at 06h 39m GMT, January 3, with sharp movements in all three elements. Horizontal intensity increased by 15 gammas, declination moved easterly by rather less than 1′, and the numerical value of vertical intensity decreased by 3 gammas. Following the sudden commencement there was a comparatively quiet period lasting almost exactly eight hours. At 14h 40m the horizontal intensity increased suddenly by 42 gammas while the other two elements barely showed a change. Wide fluctuations ensued shortly afterwards in all the elements, and lasted for about three hours, after which time the traces were only slightly disturbed until 24h. Ranges: D, 14′; H, 185 gammas; Z, 94 gammas.
The ionosphere at Huancayo, Peru, January to June, 1940
Authors: Wells H. W. , Coile R. C. 
Published: February 2008

This report is a continuation of those already published in this Journal and gives monthly mean hourly values of the heights and penetration‐frequencies of the ionospheric regions as obtained from the automatic multifrequency ionospheric recording apparatus. A complete discussion of these data will be made in an annual summary at the end of 1940.Commencing with January, 1940, some desirable changes were made in the scaling of the heights of the layers. Besides the minimum virtual height, the actual heights of maximum electron‐density, uncorrected for presence of lower layers, are now scaled, using the method described by Booker and Seaton.
Cosmic Radiation and Magnetic Storms
Authors: Hogg A. R. 
Published: February 2008

Summary—This paper deals with the results of cosmic‐radiation measurements in relation to magnetic storms during 1936–39. The results show that over this period of four years:(a) Major deviations of the cosmic‐radiation intensity were always negative in sign.(b) Such major deviations were, in the great majority, if not in all cases, associated with disturbances in the Earth's magnetic field.(c) The cosmic‐radiation disturbance usually became apparent a few hours after the onset of the magnetic storm.(d) Magnetic storms were in all cases accompanied by a decrease in cosmic‐radiation intensity, ranging from one‐half per cent to five per cent.(e) The greater the range of H during the storm, the greater, on the average, was the cosmic‐ray disturbance.(f) The average course of a cosmic‐ray disturbance bears some broad resemblance to the course of a magnetic storm.
Capetown Magnetic Observatory, January to September, 1940
Authors: Ogg A. 
Published: February 2008

January 3—There was a sudden‐commencement storm at 14 h 41 m GMT, January 3, with a sudden increase of 25 gammas in H. Ranges: D, 15′; H, 194 gammas; Z, 153 gammas.January 10—The interval from 13 h to 21 h GMT, was disturbed. Ranges: H, 118 gammas; Z, 149 gammas.
Gustaf S. Ljungdahl (1882–1940)
Authors: Åslund Sven 
Published: February 2008

By the sudden death of Dr. Gustaf S. Ljungdahl on November 2, 1940, at his home in Lidingö (near Stockholm), the Magnetic Section of the Hydrographic Service (Kungl. Sjökarteverket), and the Observatory at Lovö lost their capable chief, and magneticians in many parts of the world an esteemed colleague and friend.Gustaf S. Ljungdahl was born at Helsingborg on November 2, 1882. He attended the University of Upsala, where he received the degree of Bachelor of Arts in 1904. During 1910 to 1,912 he served as a geodesist in the General Land Survey of Sweden receiving valuable training in field survey‐work. In 1913 he continued his studies under the eminent professor of physics, Knut Ångström obtaining an M.A. degree. He was later an assistant at the Royal Nautical Meteorological Bureau (Kungl. Nautisk‐Meteorologiska Byrån) until 1921; here he had the opportunity of acquiring a thorough experience with liquid compasses. During this period he began magnetic survey‐work both on land and sea. Several of the areas of greatest local magnetic disturbance known at present in Swedish waters were surveyed and charted. In 1921 he obtained his doctorate, his dissertation being entitled “The storm‐flood in Skagerrak‐Kattegatt on December 4, 1914, and connected fluctuations of water‐level.”
The Ionosphere at Huancayo, Peru, October, 1940, to March, 1941
Authors: Wells H. W. , Ledig P. G. , Coile R. C. , Jones M. W. 
Published: February 2008

This report is a continuation of those already published in this Journal1 and gives monthly mean hourly values of the heights and penetration‐frequencies of the ionospheric regions as obtained from the automatic multifrequency ionospheric recording apparatus located near Huancayo, Peru, South America, in latitude 12° 02′.7 south, longitude 75° 20°.4 west of Greenwich, which operates over a frequency‐range 0.516 to 16.0 Mc/sec. A complete discussion of these data will be made in an annual summary.Table 1 gives the monthly mean hourly values of the actual heights of maximum electron‐density (hmax), uncorrected for retardation in lower regions2, and the minimum virtual height (hmin) for both the F1‐ and F2‐regions, the penetration‐frequencies for the E‐, F1‐, and F2‐regions, and the lowest frequency at which echoes were observed when that frequency was greater that 0.516 Mc/sec.
Sitka Magnetic Observatory, January to March, 1941
Authors: Gebhardt Robert E. 
Published: February 2008

January 17–19—A sudden commencement was recorded at 00h 10m GMT, January 17; the disturbance gradually increased but was not very great at any time. By the close of January 19 the conditions were normal. Ranges: D, 40′; H, 552 gammas; Z, 405 gammas.January 23–25—A moderately disturbed period began gradually at about 08h GMT, January 23, with the disturbance increasing gradually in intensity until about 13h, January 24. It then began to subside. The magnetic elements were normal at the close of January 25.
The Ionosphere at Watheroo, Western Australia, April to June, 1941
Authors: Parkinson W. C. 
Published: February 2008

This report is a continuation of those already published in this Journal1 and gives monthly mean hourly values of the heights and penetration‐frequencies of the ionosphere as obtained by means of automatic multifrequency ionospheric recording apparatus located near Watheroo, Western Australia, in latitude 30° 19′.1 south, longitude 115° 52′.6 east of Greenwich, which operates over the frequency‐range 0.516 to 16.0 Mc/sec.Table 1 gives the monthly mean hourly values of the height of maximum electron‐density (hmax), uncorrected for retardation in lower regions2, and the minimum virtual height (hmin) for both the F1‐ and F2‐regions, the penetration‐frequencies for the E‐, F1‐, and F2‐regions, and the lowest frequency at which echoes were observed when that frequency was higher than 0.516 Mc/sec.
Solar and Magnetic Data, April to June, 1941, Mount Wilson Observatory
Authors: Nicholson Seth B. , Mulders Elizabeth Sternberg 
Published: February 2008

The magnetic storm of May 21, 1941, ended a sequence of four which began with the great storm of March 1. Each storm of this sequence was apparently associated with a different sunspot group: That of March 1 with Mount Wilson No. 7132, 24° west, 16° north at the beginning of the storm; March 28 with No. 7156, 13° east, 8° north; April 24 with No. 7172, 7° east, 6° south; May 21 with No. 7192, 0°, 16° south. These storms, however, may have been associated with other less active groups or with hypothetical activity in the region of No. 7132, although no spot or other activity was seen in that region after it passed from view at the west limb on March 4.Small magnetic disturbances beginning on June 9 and 13, were probably associated with group No. 7201, which crossed the central meridian on June 9.3, 12° north of the center of the disk.
The Aurora and Geomagnetic Storm of September 18–19, 1941
Authors: McNish A. G. 
Published: February 2008

The greatest auroral display observed in the eastern United States during recent times accompanied the geomagnetic storm of September 18–19, 1941. Favored by a clear sky and a moonless night the phenomenon is one which will be remembered for many years by millions of people who have never before had the opportunity of witnessing a great display.Reports of the aurora have been received from many parts of this country. The most intense effects were observed in the east where they extended as far south as Florida, although accounts of the display have been received from Pasadena, California. At Washington, D.C., the auroral activity was so intense and prolonged that an auroral log was maintained throughout the night by the writer upon which the following account is based.
Summary of the Year's Work, to June 30, 1941, Department of Terrestrial Magnestism, Carnegie Institution of Washington
Authors: Fleming J. A. 
Published: February 2008

The effective investigation of the Earth's magnetism and electricity requires international collaboration since many fundamental researches depend on observations of geomagnetic and geoelectric phenomena from all parts of the world. During the year ended June 30, 1941, many of the countries from which, in the past, needed data were obtained have been enmeshed in war and thus have had little opportunity for geophysical research or collaboration. Necessarily, therefore, the activities of the Department have been directed to further detailed study of the accumulated material at hand.In the United States also many specialists were called to develop the scientific aspects of projects concerned with national defense. In conformity with the action of the Trustees, the services of the regular scientific and administrative personnel and use of equipment, site, and buildings have been contributed without cost to the Government. Thus for the year ending June 30, 1941, nearly 20,000 hours and over 5000 hours of the budgeted scientific and administrative personnel, respectively, were diverted from the Department's program of geomagnetic, geoelectric, and nuclear‐physics investigations. Five men of the regular staff are also on leave of absence at the Naval Ordnance Laboratory and the Naval Research Laboratory. Seventy‐five additional investigators, including physicists, engineers, assistants, and technicians—many through the generous granting of leave from universities and commercial organizations—had been engaged prior to June 30, 1941, to assist in development of urgent projects submitted by the Navy and Army through contracts with governmental agencies.
Apia Magnetic Observatory, July to December, 1941
Authors: Sapsford H. Bruce 
Published: February 2008

(Latitude 13° 48′.4 S., longitude 171° 46′5 or 11h 27m.4 W. of Gr.)July 4–5—A sudden commencement occurred at 03h 43m GMT, July 4, when H increased 20 gammas. The curves were slightly disturbed until 19h when the record failed. Records were not obtained again until 19h, July 5, at which time the traces were highly disturbed, H being about 200 gammas below normal. Recovery was rapid.
American URSI broadcasts of cosmic data, giving American magnetic character‐figure, CA, three‐hour‐range indices, K, and mean K‐indices, KA, for April to June, 1942
Authors: Johnston H. F. 
Published: February 2008

Summaries of American URSI broadcasts have appeared regularly in this Journal since the issue for December, 1930.As set forth in this Journal for June, 1937, “The Department of Terrestrial Magnetism and the United States Coast and Geodetic Survey with the cooperation of the United States Army and the United States Navy communication‐services and several amateur radio stations have undertaken to supply the American character‐figure based upon the reports of the seven American‐operated observatories—those of the Department of Terrestrial Magnetism at Huancayo in Peru and at Watheroo in Western Australia, and those of the United States Coast and Geodetic Survey at Cheltenham (Maryland), Honolulu (Hawaii), San Juan (Puerto Rico), Sitka (Alaska), and Tucson (Arizona).” This character‐figure is being designated CA, and its values for the first twelve, the second twelve, and all twenty‐four hours of each Greenwich day for April to June, 1942, are given in Table 1.
Dan Barfod la Cour, 1876–1942
Authors: Egedal J. 
Published: February 2008

Dan Barfod la Cour was born in Copenhagen September 12, 1876, the son of Poul la Cour, Danish physicist, who was then Superintendent at the Danish Meteorological Institute and later became teacher with the title of Professor at the most prominent Danish Folk‐Highschool.In his earlier years la Cour did not attend school regularly but took private lessons. He then entered the University of Copenhagen, where in 1902 he took the degree of M.A. In 1939 he received the honorary degree of Doctor of Science from the George Washington University of Washington, D.C.
Sitka Magnetic Observatory July to September, 1942
Authors: Pinckney Harold W. 
Published: February 2008

(Latitude 57° 03′.0 N., longitude 135° 20′1 or 9h 0lm.3 W. of Gr.)July 8–9—A disturbance beginning gradually at 00h GMT, July 8, continued through 03h, July 9. Except for sharp drops in H and Z from 09h 15m to 12h, during which time a K‐index of 8 was recorded, the variations were moderate and characterized by rapid oscillations.
Vector‐diagrams of annual variation of magnetic activity in declination and horizontal intensity, Oslo, 1843–1886
Authors: Wasserfall K. F. 
Published: February 2008

The reduction of horizontal‐intensity determinations made by Christopher Hansteen and his successors at the Oslo Observatory (latitude 59° 54′.77 north, longitude 10° 43′.4 east) during 1840 to 1930 was published in 1941 in two papers [see 1 and 2 of “References” at end of paper]. The first paper [1] contains complete daily data for horizontal intensity, H, at 09h and 14h with a short explanatory text, while the second paper [2] gives detailed data of the complicated reductions of the absolute determinations of declination, D, and includes summarized tabulations, graphs, and discussion.About two years ago the author began compilations of the daily data for D for the same interval, 1843 to 1930 [3]. These for 09h and 14h during 1843–1886, that is for four of the eight 11‐year epochs, are now completed. It seemed worthwhile to compile vector‐diagrams of the annual variations in D and H and of ΔH = (ΔH14 − ΔH09) and ΔD = (ΔD14 − ΔD09) given in Table 1.
Sitka Magnetic Observatory October to December, 1942
Authors: Pinckney Harold W. 
Published: February 2008

(Latitude 57° 03′.0 N., longitude 135° 20′.1 or 9h 01m.3 W. of Gr.)October 2–5—Beginning gradually just before 09h GMT, October 2, a disturbance of moderate severity continued through the night of October 5. K‐indices of 7 were recorded for the periods 12h–15h on October 2 and 03h–06h on October 3.
Cheltenham Magnetic Observatory October to December, 1942
Authors: Hershberger John 
Published: February 2008

(Latitude 38° 44′.0 N., longitude 76° 50′.5 or 5h 07m.4 W. of Gr.)October 2–5—A moderately severe storm began rather indefinitely at about 10h 50m GMT, October 2, and lasted until about 15h, October 5. The first ten hours of the storm were marked by very short‐period activity, particularly in H, superimposed on slower variations. The severest part of the storm came in the first six hours of October 3, during which two K‐indices of 6 were recorded. Thereafter the activity was not violent.
Huancayo Magnetic Observatory October to December, 1942
Authors: Ledig Paul G. 
Published: February 2008

(Latitude 12°02′.7 S., longitude 76°20′.4 or 5h 01m.4 W. of Gr.)October 2—Beginning at 02h 47m GMT, October 2, with a sharp short rise in H, there was a moderate magnetic disturbance which was marked by a number of narrow peaks and bays in the H‐trace with a maximum range of about 200 gammas during the daylight hours of October 2 and followed by subnormal H‐values for several days. D and Z were only mildly affected during the hours of maximum disturbance.