bluuebunny/crossref_metadata_2025_split huggingface dataset:
The eccentric dipole approximating the Earth's magnetic field
Authors: Bartels J. 
Published: February 2008

The magnetic dipole, situated at the Earth's geometric center O, and whose magnetic field furnishes the best approximation to the observed field of the Earth for the year 1922 has an axis aligned along the direction from a point A (near the geographic South Pole) to the antipodal point B on the Earth's surface, with B situated in latitude 78°.5 north and longitude 291°.2 east. The strength of the dipole is 8.1×1025 Gauss. cm3, yielding a maximal horizontal intensity of 0.315 Gauss at the Earth's surface.If the observed field is to be approximated by that of a magnetic dipole not necessarily situated at the Earth's center, the best approximation (in a sense to be defined) is furnished by a dipole of the same strength as before, and with an axis parallel to AB, the dipole being situated at a point C (magnetic center) 342 km distant from the Earth's center O and in a direction towards a point C′ in latitude 6°.5 north and longitude 161°.8 east. The field of this eccentric dipole is computed by formulae similar to those given by Adolf Schmidt, expressed in tables and charts, and discussed.The approximation of the observed Earth's magnetic field furnished by the eccentric dipole is compared with that furnished by the geometrically centered dipole (uniform magnetization) by discussing the differences, or regional anomalies. The improvement in the approximation due to the shift of the dipole from the geometric center O to the magnetic center C is hardly noticeable for the field in the Northern Hemisphere, but quite distinct in the Southern Hemisphere.
The effect of wind upon the Earth's electric field at the surface
Authors: Brown Joseph G. 
Published: February 2008

The effect of wind upon the potential‐gradient has long been a subject of study and speculation. Probably the most significant fact so far observed is that stated by C. W. Allen,1 namely, that on days of continuous wind the diurnal variation of the gradient at Mount Stromlo, Australia, approaches the unitary, or world, variation observed over the oceans, while on days with calm the departure from the variation over the ocean is much greater.In a recent paper by the author2 a method of obtaining the local diurnal‐variation by eliminating the unitary‐variation from mean curves was adopted and a theory of the local variation based upon the daily cycle of turbulence, convection, and subsidence in the atmosphere was proposed. Allen's observation is of considerable interest in connection with this theory, for if the wind blows continuously throughout the 24 hours the constant turbulence due to the wind should greatly reduce the effect of the turbulence and convection due to the heating of the surface and of the subsidence at night. On the other hand, days with calm nights and no general wind should allow these processes to take place with the greatest effect upon the gradient. To examine this result more fully, the mean local‐variations of the days of continuous wind and the days with calm at Mount Stromlo have been computed using the method referred to above. These are shown in graph A of Figure 1 along with the local variation computed from all electrically‐quiet days. It is evident from these curves that wind is an important factor in determining the amplitude and form of the local variation; it is believed that the differences here found are of the sort to be expected from a consideration of the proposed theory of the local variation.
Solar disturbance of May 25, 1937, accompanied by simultaneous magnetic, earth‐current, and ionospheric effects
Authors: Davies F. T. , Scott W. E. , Stanton H. E. 
Published: February 2008

Solar—On May 25, from 16h 51m to 17h 05m GMT, a bright active flocculus was observed on the Sun at latitude 19° south and longitude 50° west from the central meridian.Magnetic—The horizontal‐intensity component H increased 118 gammas between 16h 51m and 17h 01m, then decreased less rapidly to normal value by 17h 20m. The declination decreased one minute of arc during this interval and returned to normal value. The vertical‐intensity component Z increased 3 gammas and then decreased 15 gammas between 16h 52m and 17h 05m.
ATMOSPHERIC ELECTRICITY AT THE COLLEGE‐FAIRBANKS POLAR YEAR STATION
Authors: Sherman K. L. 
Published: February 2008

The atmospheric‐electric program at College, Alaska, during the second International Polar Year extended from October 1, 1932, to August 31, 1933. (1) Continuous registration was made of air‐potential with a recording quadrant‐electrometer and a radioactive collector on a horizontal rod at the variation‐observatory and during most of the time also with a recording bifilar‐electrometer with radioactive collectors exposed by the stretched‐wire method for control at a standardization‐station. (2) Continuous registration was made of air‐conductivity due to both positive and negative ions, using semi‐portable apparatus in which the deflection is nearly proportional to the conductivity; in this apparatus the charge collected by the Gerdien condenser flows to earth through a resistance of about one electrostatic unit and the resulting voltage‐drop through this unit is recorded by a single‐fiber electrometer. (3) Determinations of the number of positive and negative small ions, usually made once each day, using a modified Ebert ion‐counter. (4) Determinations of the number of condensation‐nuclei, once daily from late in March through August, using an Aitken counter; during the cold weather the counter did not function satisfactorily.These data conform with those obtained in lower latitudes at stations on land that are relatively free from variable sources of pollution. The average gradient for all complete days for the eleven‐month period is 104 volts per meter with a maximum in January and a minimum in August. Harmonic analyses of the hourly values show that a 24‐hour component exists in gradient, in substantial agreement with Mauchly's findings. All complete days of positive and negative conductivity yield average values of 179 and 131 × 10−6 electrostatic unit, respectively. The variations are approximately the inverse of those in the gradient although their product—the electrical conduction current—shows regular daily and seasonal variations. The average number of positive small ions by months varied from a minimum of 620 per cc in July to a maximum of 980 in November. The number of negative small ions varied from 520 per cc in July to 660 in November and February. From the ion‐count and the corresponding values of conductivity a mean value of 1.56 cm2 volt−1 sec−1 for the mobility of both the positive and negative small ions was found, although different mobility‐groups are indicated by frequency‐curves. The average of 112 determinations of nuclei is 3760 per cc.The electrode‐effect appears to be quite important at this station. The ratio of positive to negative conductivity varies directly as the gradient, both in long‐period and short‐period changes. This and other features of the results are explicable on the basis of conditions as they would exist in quiet air. At times turbulence is effective in complicating the relations between the elements and so for a complete explanation of these results the effect of mixing must be considered in addition to conditions as they would exist in quiet air.
Final relative sunspot‐numbers for 1936 and monthly means of prominence‐areas for 1909‐1936
Authors: Brunner W. 
Published: February 2008

Table 1 contains the final sunspot‐numbers for 1936, for the whole disc of the Sun, based on observations made at the Zürich Observatory, supplemented by series furnished by other cooperating observatories for days (indicated by asterisks) on which no observations were possible at Zürich.Table 2 gives the yearly means of the relative numbers, R, since the last minimum 1933 and the number of days without spots.
Cheltenham Magnetic Observatory, October to December 1937
Authors: Ludy Albert K. 
Published: February 2008

(Latitude 38° 44′.0 N., longitude 76° 50′.5 or 5h 07m.4 W. of Gr.)October 3–4—A storm began abruptly at 11h 19m GMT, October 3, with an increase of 12 gammas in H. It progressed mildly with short‐period oscillations until midnight of October 3. The storm then entered into a severe phase lasting about ten hours. During this time there were rapid changes of great amplitude and the extreme values of all three elements occurred about 06h. Ranges: D, 77′; H, 370 gammas; Z, 350 gammas.
Huancayo Magnetic Observatory, October to December 1937
Authors: Davies Frank T. 
Published: February 2008

(Latitude 12° 02′.7 S., longitude 75° 20′.4 or 5h 01m.4 W. of Gr.)October 3–4—A sudden commencement of relatively small amplitude occurred in all three elements at 11h 22m GMT, October 3. H decreased 2 gammas and then increased 17 gammas in two minutes. In the same interval D moved westerly 1′ and Z increased 5 gammas. The traces were very disturbed from this time until the end of October 4, a marked feature of the storm being a minimum bay in H from 00h to 12h, October 4.
Cheltenham Magnetic Observatory, April to June 1938
Authors: Ludy Albert K. 
Published: February 2008

(Latitude 38° 44′.0 N., longitude 76° 50′.5 or 5h 07m.4 W. of Gr.)April 13–15—A moderate disturbance began at 08h 40m GMT, April 13, and continued until 02h, April 15. The storm was characterized by great short‐period activity of not very large range. Ranges: H, 188 gammas; Z, 178 gammas; D, 30′.
Remarks Dr. Chapman's note on radio fade‐outs and the associated magnetic disturbances
Authors: Appleton E. V. 
Published: February 2008

This letter is by way of an addendum to the communication of Professor S. Chapman1 and the further communication by S.S. Kirby2 which it prompted.Mr. Kirby has given a useful analysis of the steps by which the relations between radio fade‐outs and their associated solar and magnetic disturbances have been gradually elucidated during the last two and a half years by American workers, but the story seems to me to be incomplete, since no mention is made of the work of Mögel, the pioneer investigator of such matters.
Sitka Magnetic Observatory July to September, 1938
Authors: Gebhardt Robert E. 
Published: February 2008

(Latitude 57° 03′.0 N., longitude 135° 20′.1 or 9h 01m.3 W. of Gr.)July 4–5—A slight magnetic disturbance began gradually at about 03h GMT, July 4, and increased slowly to maximum intensity between 12h and 14h. Thereafter the elements gradually returned to normal values at about 07h GMT, July 5. Ranges: D, 79′; H, 553 gammas; Z, 488 gammas.
Auroral work in southern Norway in the year 1938
Authors: Störmer Carl 
Published: February 2008

(1) Introduction—Since 1911 I have had in operation a series of permanent stations in southern Norway to photograph the polar aurora and to measure its height by simultaneous exposures from different stations connected by telephone‐lines. A report of the work from 1911 to 1922 has been issued but only a small part of the extensive material obtained since 1922 has as yet been published.In recent years I have examined this material which consists of more than 25,000 negatives and have prepared an auroral log for the years 1923 to 1937. In this log, which is perhaps too extended for publication, each picture has been examined carefully and the following data have been noted: Number of exposure, station, time, exposure, auroral form, stars, number of points measured, and general remarks. This log contains 11,338 successful pictures and among these about 6,484 sets of simultaneous photographs for determination of height. Of these 6,484 sets only a few have been measured and calculated, but these have furnished 4,683 heights of which only selected ones have been published.
Final relative sunspot‐numbers for 1938 and monthly means of prominence‐areas for 1931–1938
Authors: Brunner W. 
Published: February 2008

Table 1 contains the final sunspot‐numbers for 1938, for the whole disk of the Sun, based on observations made at the Zürich Observatory, supplemented by series furnished by other cooperating observatories for days (indicated by asterisks) on which no observations were possible at Zürich.Table 2 gives the yearly means of the relative numbers, R, since the last minimum 1933 and the number of days without spots.
An unusual magnetic disturbance
Authors: Howe H. Herbert 
Published: February 2008

A rather unusual magnetic disturbance occurred on June 26, 1939. Figure 1 is reduced from actual tracings of the curves registered at the five magnetic observatories of the United States Coast and Geodetic Survey during the interval 20h to 22h GMT, June 26, 1939. Unfortunately, there was a slight artificial disturbance at Tucson just before the beginning of the natural disturbance, caused by a truck used in connection with the construction of the new variation‐building.All five observatories show sudden commencements at about 20h 20m GMT, marked chiefly in four cases by an increase in horizontal intensity. After about an hour, the curves returned to normal, in two abrupt steps separated by about seven minutes. The duration of this disturbance was about the same as that of a bay, but it is different from an ordinary bay because of the abrupt increase and decrease.
Cheltenham Magnetic Observatory April to June, 1939
Authors: Ludy Albert K. 
Published: February 2008

April 4–5—A mild disturbance of short duration took place between 18h 35m GMT, April 4, and 8h, April 5. Ranges: D, 23″; H, 78 gammas; Z, 43 gammas.April 16–22—An abrupt commencement of a storm occurred at 21h 29m GMT, April 16. In the first few hours the storm was very moderate but at 0lh 58m, April 17, it suddenly became very severe. The greatest ranges of the storm occurred between 06h and 08h, April 17. During this interval the range of H was 664 gammas. The interval between 08h and 20h, April 17, was marked by great short‐period activity of moderate range in all three elements. From 20h to 22h the ranges again became relatively large. The main phase of the storm ended at 21h 35m, April 17, but the field continued to be moderately disturbed until 03h, April 22. Ranges: D, 47″; H, 664 gammas; Z, 515 gammas.
On the existence of a biannual component in the F2‐layer ionization
Authors: Eckersley T. L. 
Published: February 2008

§1. Introduction—The problem of the mode of ionization of the ionosphere is of great physical interest. It is known that the ionosphere consists of three well‐defined regions, the E‐, F1‐, and F2‐layers, and that whereas the main features of the mechanism of the ionization of the E‐ and F1‐layers are known, there are many problems associated with the mode of ionization of the F2‐layer which remain as yet unsolved.From the general nature of the diurnaI variations in the ionic density in the E‐ and F1‐layers, as deduced from critical escape‐frequencies measured at vertical incidence, it is obvious that the ionization is at least in part related to the Sun's radiation. It is now generally accepted that the E‐ and F1‐layers are mainly ionized by ultraviolet radiation from the Sun. There is some abnormal sporadic ionization which does not appear to be of solar origin, for instance, the ionization which is reponsible for the reflection of 7‐ to 10‐meter waves to distances of 1000 km or so, and which does not apparently vary with the sunspot‐cycle, and the sporadic ionization which persists throughout the long polar winter night. But the main E‐ and F1‐ionizations have been shown to obey the law deduced theoretically by Chapman for a region of the atmosphere ionized by a monochromatic radiation from the Sun, namely that the midday critical frequency should vary as cos¼θ, where θ is the zenithal angle of the Sun. The wave‐lengths of the ionizing radiations and the precise molecular or atomic reactions involved are as yet unknown, as it would need a complete spectroscopic analysis in the ultraviolet region of O, N, O2, and N2 in their various excited and ionized states to determine them. Eclipse experiments on the accompanying changes of density during the optical eclipse also confirm the idea that the ionization of the E‐ and F1‐layers is mainly due to ultraviolet light from the Sun.
Provisional solar and magnetic character‐figures, Mount Wilson Observatory October to December, 1939
Authors: Nicholson Seth B. , Mulders Elizabeth Sternberg 
Published: February 2008

The disturbance of October 3 to 4 was not like that of a typical magnetic storm, although the range in H was large. The largest spot‐group on the Sun was Mount Wilson No. 6623, which crossed the central meridian on October 4.2, 14° north of the center of the disk.The magnetic storm of October 13 to 15 was probably associated with the active group No. 6633, which crossed the central meridian on October 12.3, 12° south of the center of the disk.
The magnetic observatory at Toolangi
Authors: Baldwin J. M. 
Published: February 2008

The magnetic observatory at Toolangi is now in full operation again, the recording having started in January 1940. Careful consideration was given to the question of underground construction and its adoption resulted from the decision that it was better to run the risk of dampness than the local risk of loss through forest fire.The new building is of concrete with three feet of earth over the roof. The building is entirely covered with waterproof coating outside and below which there is adequate provision for efficient drainage, all drainage water being discharged some distance down the hillside. All material used in the building was tested and is non‐magnetic.
Sitka Magnetic Observatory January to March, 1940
Authors: Gebhardt Robert E. 
Published: February 2008

(Latitude 57° 03′.0 N., longitude 135° 20′.1 or 9h 01m.3 W. of Gr.)January 3–4—A small storm began abruptly at 14h 41m GMT, January 3, with a sharp decrease in the horizontal intensity. The field was very disturbed from 15h to 17h. Thereafter the trace began a gradual return to normal values. The disturbance ended about 24h, January 4. At times during the stormiest period the spots moved so rapidly, it was not possible to separate the three components. Ranges: D, 170′; H, 1172 gammas; Z, 1135 gammas.
Cheltenham Magnetic Observatory January to March, 1940
Authors: Ludy Albert K. 
Published: February 2008

(Latitude 38° 44′.0 N., longitude 76° 50′.5 or 5h 07m.4 W. of Gr.)January 3–4—A mild storm, which was very active during the first two hours, began at 14h 41m GMT, January 3, when H decreased 158 gammas in 23 minutes. The storm ended at 05h, January 4. Ranges: D, 26′; H, 265 gammas; Z, 54 gammas.
A New Laboratory for Cosmic‐Terrestrial Research
Authors: Stetson Harlan True 
Published: February 2008

An initial grant from the American Philosophical Society1 in 1935 for investigations in cosmic‐terrestrial relationships together with additional funds from anonymous sources has made possible the inauguration of a program of needed observations in geophysical phenomena that has recently resulted in the establishment of a new laboratory for cosmic‐terrestrial research at Needham, Massachusetts.The site of the new Laboratory (Fig. 1) was selected after about a year of careful study of the environs of Boston from the point of view of suitability as to appropriate conditions for atmospheric‐electric observations, together with accessibility to the Massachusetts Institute of Technology with which the work at the Laboratory is associated.
Internationale Erdmagnetische Charakterzahlen im Jahre 1940
Authors: Bartels Von J. 
Published: February 2008

Zur Reproduktion werden vorgeschlagan:**1940—März 24 u. 29; September 26, 15 Uhr bis September 27, 9 Uhr.*1940—Januar 3; April 2 u. 25; Juni 25; Juli 13; August 3; Oktober 7 u. 8; November 25.Zahl der Observatorien, deren Charakter‐Schätzungen verwendet werden konnten: 53 im Januar und Februar; 54 im März; 56 im April, Mai, Juni; 58 im Juli; 57 im August bis November; 58 im Dezember.
In Memoriam Doctor Garmt van Dijk, 1877–1940
Authors: Cannegieter H. G. 
Published: February 2008

In the last days of the year 1940 the Netherlands Meteorological Institute has suffered a sad bereavement in the death of the member of its scientific staff, Dr. G. van Dijk. After a short illness he died suddenly and quite unexpectedly in the night of December 19, 1940, at the age of 63 years. Thirty‐four years of a busy life had been devoted to the organization and direction of the Magnetic and Seismological Section of the De Bilt Meteorological Institute.Van Dijk was born June 22, 1877. He studied at the University of Groningen and was given the degree of Doctor of Physics March 4, 1905. On February 1, 1907, he was appointed by the Institute at De Bilt as Assistant Director in charge of the Section of Magnetism and Seismology. After his plans new pavilions were constructed for the magnetic and seismological instruments. The seismological pavilion was finished in 1911 and the magnetic pavilion in 1913.
Erdmagnetisch ruhige und gestörte Tage im zweiten Halbjahr 1940
Authors: Bartels J. 
Published: February 2008

An die Herren Direktoren der erdmagnetischen Observatorien:Dr. G. van Dijk ist am 19. Dezember 1940 gestorben; H. G. Cannegeiter hat ihm in Hemel en Dampkring [39, 1–3 (1941)] einen Nachruf gewidmet.
Sitka Magnetic Observatory, April to June, 1941
Authors: Gebhardt Robert E. 
Published: February 2008

April 19—A short period of increased activity began gradually at 05h GMT, April 19. Maximum storminess occurred between 08h and 09h with decreased values of all elements. After 09h conditions slowly returned to normal.April 24–25—A small magnetic storm began abruptly at 08h 39m GMT, April 24. The activity increased gradually until about 15h and then began a gradual decrease. The disturbance consisted of large bays. After 15h a short‐period vibration was superimposed on the long‐period motion. After 08h, April 25, there was a slow return to normal. Ranges : D, 126′; H, 884 gammas; Z, 804 gammas.
Note on the Effect on Cosmic‐Ray Intensity of the Magnetic Storm of March 1, 1942
Authors: Lange Isabelle , Forbush S. E. 
Published: February 2008

Figure 1 shows the decrease in cosmic‐ray intensity (corrected for barometric pressure) recorded at Cheltenham (Maryland) and Huancayo (Peru) during the magnetic storm of March 1, 1942, which began with an abrupt sudden commencement at 02h 30m (75° west meridian mean time). It will be noted that the decrease in cosmic‐ray intensity occurred immediately after the sudden commencement and was followed by large changes in cosmic‐ray intensity.The change of cosmic‐ray intensity in Figure 1 is remarkably similar to that recorded during the five days following the sudden commencement of the magnetic storm of January 16, 1938 [see Fig. 2 of paper by S. E. Forbush, Terr. Mag., 43, 203–218 (1938)]. These curves are much like those for the average storm‐time variations in magnetic horizontal intensity [see paper by S. Chapman, Terr. Mag., 40, 349–370 (1935) and also E. H. Vestine, Terr. Mag., 47, 97–113 (1942)], which is strong indication that the changes in cosmic‐ray intensity are due to the magnetic field of the storm.