bluuebunny/crossref_metadata_2025_split huggingface dataset:
The times of recent “sudden commencements” of magnetic storms at Eskdalemuir
Authors: Absalom H. W. L. 
Published: February 2008

The publication by Dr. R. Bock of the times of several recent “sudden commencements” of magnetic storms registered at Potsdam, by means of recording arrangements permitting a more accurate determination of occurrence than those in everyday use at most magnetic observatories, suggests that similar information from another observatory may be of interest.Although there is at present at Eskdalemuir (lat. 55° 19′ N.; long., 3° 12′ W.) no means of obtaining continuous open time‐scale registration of the horizontal force or declination, it is possible to give for the last five of the Potsdam cases, and with at least as much accuracy, the times of the “sudden commencements” in the vertical component. These times are derived from records of the rate of change of vertical force, the records being obtained from a sensitive moving‐coil galvanometer connected to the ends of a coil of insulated wire resting in an approximately horizontal plane. The resistance of the circuit is such that the galvanometer is adjusted to critical aperiodicity. This method of registering small changes in vertical force was introduced at Eskdalemuir by Dr. A. Crichton Mitchell some eight years ago, but it is only since the end of January, 1926, that records have been obtained continuously. Particulars of the arrangements and a description of the changes in vertical force during a small “sudden commencement” at 1924, September 4, 5h 45.3m G. M. T., have already been published. For the present purpose it is sufficient to state that on the photographic record the time‐scale is about 10 millimetres to 1 minute, and that a deflection of about 6 millimetres is produced by a rate of change in vertical force of 10−7 c. g. s. per second. Short time‐gaps every minute, and somewhat longer gaps every hour, are made on both the base line and the trace of the galvanometer deflection by an electromagnetic shutter actuated by a contact‐clock which is rated from daily time‐signals from Greenwich. The time of occurrence of a reasonably well‐defined movement on the record can be assigned to well within 0.1 minute.
Magnetic observations in Spitzbergen in 1927
Authors: Woolley R. v. d. R. 
Published: February 2008

The following observations were made by the writer of this article while a member of a Cambridge University expedition to Edge Island, the southeast member of the Spitzbergen group, in July and August 1927. The instruments used were a Kew pattern unifilar magnetometer, by Dover, Charlton (No. 161), a 3‐inch theodolite (used in some of the declination observations), and a chronometer which was checked by wireless time‐signals.Values of horizontal force were observed at six stations grouped round Stor Fiord, three on the islands and three on the mainland of Spitzbergen. The procedure adopted in every case was to perform successively vibration, deflection (30 cm.), deflection (40 cm.), deflection (30 cm.), and vibration experiments. Before leaving England the instrument was compared with the standard instruments at Abinger and a satisfactory agreement obtained. The declination was observed at seven separate stations, usually at intervals whenever convenient during the horizontal‐force experiment. Very little meaning can be attached to a single observation of declination in these latitudes, but by taking observations over two hours on a quiet day a mean value can be found. On very quiet days the needle may not move through more than three or four minutes of arc during two hours. The Sun was used for all azimuths, which were sometimes determined with the theodolite and sometimes with the magnetometer‐attachment.
A note on two apparent large temporary local magnetic disturbances possibly connected with earthquakes
Authors: Chapman S. 
Published: February 2008

(1) The two reports from ships, reproduced and discussed in this Note, were communicated to me by Professor H. H. Turner (President of the Section of Seismology of the international Union for Geodesy and Geophysics), with the suggestion that they were worth bringing to the notice of workers on terrestrial magnetism.I—(From Seismological Despatches, Georgetown, U.S.A., 1926, August 3., S.S. West Holbrook.)“While the above‐named vessel was entering the Gulf of Tokyo, 6:40 P.M. A.T.S. (apparent time of ship), on the above‐named date, a slight tremor was felt, as if vessel was grounding. Vessel shivering and a noise was heard, as if touching a rocky ledge, but no reduction in speed could be noticed.“Vessel heading at the time 328° P.S.C., 319° true. Deviation 3.°6 west on course.“Bearings were immediately taken of Suno Saki Light bearing north 26° east true, and Merano Hana Light bearing north 93° east true; which placed vessel in latitude 34° 55′ north, longitude 139° 43′ 30″ east, and by chart in from 46 to 50 fathoms of water.“From the above position to Yokohama, the ship's compasses were acting queerly, having on northerly courses a deviation of 0°.5 west; where before there had been 3° west.“Upon arrival in Yokohama learned that an earthquake had taken place.“The following morning, August 4, azimuths were taken for recording deviation. The compasses were still found to be out. On August 5 azimuths were again taken and compasses were now found to be back to normal.”
Variation of the compass south of Franz Joseph Land
Authors: Collinder P. 
Published: February 2008

When navigating northwest of Novaya Zemlya and south of Franz Joseph Land the masters of sealing‐ vessels do not correct their courses for variation of compass, as it is said that their dead‐reckoning will be erroneous by the amount of variation corrected for.On the motor‐cutter Björnöy, when proceeding from Admiralty Peninsula to 77° 30′ north, 59° 00′ east, thence to 78° 30′ north, 45° 00′ east, and thence to 77° 50′ north, 40° 0′ east, no correction for variation was used, and the courses laid down agreed well with astronomical positions.
Results of Earth‐current observations at Huancayo Magnetic Observatory, 1927–1929
Authors: Gish O. H. , Rooney W. J. 
Published: February 2008

The apparatus and equipment used and the natural features concerned with the measurement of earth‐current gradients at the Observatory maintained by the Carnegie Institution of Washington near Huancayo, Peru, are described. A dual system of electrodes is installed and the potential differences are registered by a recording potentiometer. Although the region embraced by the measuring system is fairly flat yet evidence is found which indicates that the general northwesterly direction of water‐course and mountain ridges here doubtless influences the direction of the electric currents.The character of the diurnal variation, as derived from records for all complete days, is exhibited by means of charts and tables and the Fourier coefficients of the diurnal variation are given for the three‐year means, for the means of individual years, and for the three‐year means grouped by months. The mean diurnal‐range of the northward component is 2.83 mv per km. The maximum occurs at 9h, the minimum at 15h (75° west meridian mean time) and the amplitudes during the hours of darkness are relatively small. The same description applies to the component at right‐angles to this (values being considered positive for currents flowing eastward) except that the mean range (3.26 mv per km) is somewhat greater. The direction of the current is northwestward from 2h.5 to 12h.5 and southeastward the remainder of the 24‐hour period. The times of the daily maximum and minimum are constant throughout the year, whi:h is contrary to the findings at Berlin, Ebro, and Watheroo. However, in general agreement with the results at these other places, the mean diurnal‐range changes with season, the principal minima (northward 1.89 mv per km, eastward 2.18 mv per km) occurring in June and maxima (northward 3.50 mv per km, eastward 4.00 mv per km) in March and October.Disturbances (variations of relatively short and irregular period with amplitudes considerably greater, in the average, than those of the diurnal variation) predominate during the daylight hours.
Ein Vorschlag zur Ergänzung der magnetischen Jahrbücher
Authors: Fanselau Von G. 
Published: February 2008

Für sehr viele magnetische Untersuchungen, die auf die Originalangaben der magnetischen Jahrbücher zurückgreifen, ist es ein oft sehr störend empfundener Übelstand, dass die von einer festen Abzugszahl aus gerechneten, veröffentlichten Werte durch die Säkularvariation besonders für weit auseinander gelegene Zeitpunkte ihre Vergleichbarkeit verlieren. Auf diesen Übelstand ist vor allem von Ad. Schmidt aufmerksam gemacht worden, auf dessen Veranlassung hin im Potsdamer Jahrbuch wohl auch zuerst diesem Umstand Rechnung getragen wurde.Den Verfahren zur Elimination der Säkularvariation liegt gewöhnlich die Annahme eines zeitlich linearen Ganges dieser Erscheinung innerhalb eines Jahres zu Grunde. Diese Annahme ist in voller Schärfe sicher nicht erfüllt, und infolgedessen muss ein solches Eliminationsverfahren notwendig einige Unsicherheiten in sich tragen. Die explizite Berücksichtigung des säkularen Ganges während eines Tages ist daher im allgemeinen wohl kaum erforderlich, ganz abgesehen davon, dass die dann vielleicht zu bildenden Stundenkorrektionen in der weitaus grössten Mehrzahl der Fälle so klein sind, dass sie weit unter der bisher zu erreichenden Genauigkeit liegen. Hinzu tritt noch die eben erwähnte tatsächlich vorhandene Unsicherheit in der Erfassung der Säkularvariation, deren wahre Grosse kaum sicher genug abgeschätzt werden kann. Im allgemeinen erscheint es daher angebracht bei den Säkular korrektionen nicht über die Tageskorrektionen hinaus zu gehen. Um hier nun ohne viel Aufwand an Arbeit dem Benutzer die Möglichkeit zu geben, sich über die Grosse des säkularen Ganges zu orientieren, schlage ich vor, dass die Observatorien in ihren Jahrbüchern laufend eine Tabelle bringen, die die Säkularkorrektionen der zur Veröffentlichung gelangenden drei Elemente enthält gültig für die Mitte des Monats. Ferner in einer weiterer Tabelle die Tageskorrektionen für die Tagesmitte bezogen auf die bereits angegebenen Monatskorrektionen. Als Genauigkeit dieser Korrektionen dürfte wegen der bereits genannten Unsicherheit der Säkularvariation im allgemeinen 0′.1 bei den Richtungsangaben und ein γ bei den Kraftangaben ausreichen. Solche Tabellen sind aus Anlass einer grösseren Untersuchung über die Nachstörung am Potsdamer Observatorium für eine ganze Reihe von Jahrgängen verschiedener Observatorien berechnet worden. Sie werden demnächst gesondert für sich zur Veröffentlichung gelangen, um die hier einmal geleistete Arbeit auch für andere Untersuchungen nutzbar zu machen.
Auroral observations at the Alaska Agricultural College and School of Mines, 1930–31—Concluded
Authors: Fuller Veryl R. 
Published: February 2008

Aurora journal, November 17, 1930, to April 17, 1931—The following pages summarize the journal of the photographic work done. Many of the photographs taken were either spoiled due to the plate‐holders leaking light, too short an exposure, or to the unusability of the negatives due to indistinct outline.November 17, 1930: The aurora was first seen at 18:00 rather dimly as a narrow arc. Observers went to Station 2 but no pictures were taken because the aurora was too weak. It died out completely at 23:00. The sky became overcast about 24:00 and continued so during the remainder of the night.
Problems in atmospheric electricity at Apia, Western Samoa
Authors: Sanderson K. C. 
Published: February 2008

Determination of influence of height of tide on reduction‐factor of Lagoon‐Station, August 3, 1931All previous determinations of the reduction‐factor for the lagoon‐station at the Apia Observatory have been made either at Watson's Island, about one‐quarter mile east of the lagoon‐house, or in the lagoon southward from the main observatory buildings. The actual places used were in the first case a flat rocky shelf and in the other a flat stretch of sand both of which are laid bare at low‐tide. Since the flat stretches are covered with water before half‐tide, observations have thus been confined to low‐water or thereabouts. It was thought that the rise and fall of the sea‐level with the tide had no influence on the reduction‐factor on account of the concrete platform about eight feet square beneath the collector, which formed a permanent earth‐plane.
American URSI broadcasts of cosmic data
Authors: Clarke Katharine B. 
Published: February 2008

The data for terrestrial magnetism, sunspots, solar constant, and aurora are the same as given in previous tables.The first three columns of the Table give (1) the magnetic character according to the scale 0–2 of the International Commission of Terrestrial Magnetism and Electricity, (2) the type featuring the day other than normal by the letters b, p, o, and i for days marked by bay, rapid pulsations, long‐period oscillations, and irregular oscillations, respectively, and (3) the hour and minute of Greenwich mean time marking the beginning of a storm, the end of the storm being indicated in the footnote to the Table. The next two columns give the data relating to sunspots: (1) the number of groups of spots and (2) the total number of spots. It is to be noted that sunspot‐numbers such as those from Zürich can be obtained from the number of groups and spots given in the Table by the formula N = k (10g + s), where k for Mount Wilson is about 0.77. The sixth and seventh columns show (1) the value in calories of the solar constant, and (2) by letters s, f, and u, whether the determination was satisfactory, fair, or unsatisfactory, respectively.
Período diurno, anual y secular en las perturbaciones súbitas del campo magnético terrestre
Authors: Rodés Por Luis 
Published: February 2008

Amablemente inivitado por el Director del Departamento Magnético de la Carnegie Institution a colaborar al numéro extraordinario de Terrestrial Magnetism and Atmospheric Electricity que dicha Institución quiere dedicar a la memoria del malogrado Director, Dr. Louis Agricola Bauer, y recordando su constante interés y extensos trabajos en el estudio de los comienzos súbitos de las tempestades magnéticas, me ha parecido tomar como tema de esta brève comunicación el estudio de la frecuencia periódica con que se producen los saltos bruscos de los imanes en el registre del campe magnético.Como base del estudio, el P. Puig ha recorrido todas las curvas del archive del Observatorio, unas 10,000 en conjunto, y de ellas ha entresacado 218 saltos bruscos, los cuales, clasificados por el mismo Padre siguiendo las indicaciones del autor de estas lineas, son analizados en este trabajo. Conviene notar que la seleccion se hizo con un criterio del todo ajeno al fin a que se destinaban, para evitar asi toda influencia de ideas preconcebidas.
American URSI broadcasts of cosmic data
Authors: Clarke Katharine B. 
Published: February 2008

The data for terrestrial magnetism, sunspots, and aurorae are the same as given in previous tables.The first three columns of the Table give (1) the magnetic character according to the scale 0–2 of the International Commission of Terrestrial Magnetism and Electricity, (2) the type featuring the day other than normal by letters b, p, o, and i for days marked by bay, rapid pulsations, long‐period oscillations, and irregular oscillations, respectively, and (3) the hour and minute of Greenwich mean time marking the beginning of a storm, the end of the storm being indicated in the footnote to the Table. The next two columns give the data relating to sunspots: (1) the number of groups of spots and (2) the total number of spots. It is to be noted that sunspot‐numbers such as those from Zürich can be obtained from the number of groups and spots given in the Table by the formula N=k (10g+s), where k for Mount Wilson is about 0.77.
A possible test for theories of magnetic diurnal‐variations and of magnetic storms
Authors: McNish A. G. 
Published: February 2008

Three plausible theories1 have been offered to explain the magnetic diurnal‐variations—the atmospheric‐dynamo theory as suggested by Balfour Stewart and extended by Schuster and Chapman, the diamagnetic theory as outlined by Gunn, and the drift‐current theory as developed by Chapman as a natural consequence of the conditions necessary to the diamagnetic theory. Regardless of the spontaneous merits of these theories, much information concerning their respective probabilities should be derivable from the study of radio‐wave reflections from the ionosphere.The atmospheric‐dynamo theory ascribes the magnetic variations to currents flowing in the ionosphere induced by the tidal motions of the air. Gunn2 has questioned the possibility of such currents because in the region of long free‐paths the average motion of the ions will be in the direction at right‐angles to the magnetic and electric fields present rather than in the direction of the induced electromotive‐force. This objection is in part unwarranted because in middle and high latitudes the ions, carried by the moving air‐masses, will have their motions diverted by the Earth's magnetic field exactly as if the induced electromotive‐forces, to which they presumably cannot respond, were acting upon them. However, in equatorial regions where the vertical component of the Earth's magnetic field is practically zero, this condition does not exist and the current‐systems cannot close in the regions of long free‐paths. An accumulation of charge would result, positive to the west and negative to the east of the noon meridian, and, in spite of the electrostatic field thus set up, no current would flow unless the mean free‐path of the ions is short as compared with the radii of curvature about the magnetic lines of force due to their gas‐kinetic velocities. From our facts and surmises concerning the ionosphere it follows that, although the diurnal‐variation currents in middle and high latitudes may have their seat in the richly ionized portion of the upper ionosphere, the closing of the current‐systems must occur much nearer the Earth's surface where the mean free‐path is short—presumably in the E‐layer.
Aurora of January 27, 1935, at Alexandria Bay, New York
Authors: Manning Douglas F. 
Published: February 2008

As the aurora has been a rather rare occurrence for several months, I thought the following report might be of interest.Between 19h and 20h 30m January 27, a quite brilliant and active aurora was observed at Alexandria Bay, New York (latitude 44° 20′ north, longitude 75° 55′ west) beginning promptly at 19h. It started as a pale green arch, the lower segment of which was about 20° exactly over the northern horizon, and could be designated as HA (2) according to the Photographic Atlas of Auroral Forms, published by the International Union of Geodesy and Geophysics. It gradually became brighter and higher and was soon accompanied with streamers of greenish hue, RA (25–26 of the Atlas). At this time patches of intense green light would develop with tinges of pink and yellow, such bundles of rays seeming to turn and move rapidly about and to the west. All this time this aurora was working higher towards the zenith but never higher than 35° to 40°. At one time a patch of whitish light was seen in the east near the zenith but this soon died away. After considerable activity with constantly changing rays kindling and dying out with at times intense colors of greenish hue, the aurora gradually spread all over the northern sky and then finally died out entirely. At 20h 30m there was only a faint glow. At the time of observation the sky was absolutely clear with light northwest winds and the temperature — 18°F.
Huancayo Magnetic Observatory January to March, 1935
Authors: Torreson O. W. 
Published: February 2008

(Latitude 12° 02′.7 S., longitude, 75° 20′.4 or 5h 01m.4 W. of Gr.)January 27–28—This storm, of comparatively short duration, is conspicuous not only for a sudden commencement in all three elements, but also for two subsequent sudden and large changes in H. The sudden commencement occurred at 14h 49m, G. M. T., with an increase, within a period of five minutes, of 105 gammas in II, an increase of 4 gammas in Z and an increase of 2′ in D. There followed minor peaks and bays in H, while D and Z were little disturbed, until 18h 17m. Then, in six minutes, H decreased 102 gammas, Z decreased 3 gammas, and D first increased 1′ and then decreased 2′. Again, from 19h 46m to 19h 50m there was a sudden decrease in H of 71 gammas, and of 1′ in D, but no effect in Z. Thereafter H, showing various peaks and bays, remained lower than normal for several hours, reaching a minimum at 0h 58m on January 28 then gradually recovering to normal values by 12h. Between 12h and 22h on January 28, various small peaks and bays were superposed on the normal diurnal trend. D and Z were little disturbed subsequent to the second sudden change described above.
On the principles of magnetic cartography
Authors: Weinberg Boris 
Published: February 2008

The purpose of a magnetic chart is to represent graphically the distribution of one or several magnetic elements over a portion of the Earth's surface or over the entire surface of the globe. The variation of the element with altitude is rarely charted.If the net of magnetic stations were sufficiently dense that an interpolation between the observed values of the element in question for points where no observations have been made, would involve no appreciable error, the magnetic chart could be considered as representing the true or real distribution of the element. Such an interpolation is justified only if we are sure that the survey has disclosed all places of extreme values—maxima and minima—of the element. But this applies only to very detailed microsurveys for which the mean distance between the extremes of magnetic elements is of the order one km1. Accordingly the great majority of magnetic charts represent the smoothed2 or normal distribution of the magnetic elements3.
The Warsaw meeting of the Commission of Terrestrial Magnetism and Atmospheric Electricity, September 1935
Authors: Laursen V. 
Published: February 2008

The meeting opened September 2 but most of the members present, together with several others interested, had met September 1 for which day an excursion to the Swider Magnetic Observatory had been arranged. The Observatory with its installations and fairly complete instrumental equipment made a very favorable impression as did also the hospitable reception accorded the visitors by Professor Kalinowski and his family.The official meeting was opened by the President, Professor Ch. Maurain, the following countries being represented by 17 members of the Commission, and other interested persons who attended the sessions and took part in the deliberations: Austria, Canada, China, Czechoslovakia, Denmark, East Africa, Finland, France, Germany, Great Britain, Holland, Italy, Japan, New Zealand, Norway, Poland, Spain, Sweden, and Switzerland.
Correlation of auroral and magnetic activities for different periods of the night at Chesterfield, Canada, 1932–33
Authors: Davies F. T. 
Published: February 2008

In the September number of this Journal (p. 267), correlation of auroral and magnetic activities was discussed using the twelve‐hour night period as a basis. At the suggestion of Professor S. Chapman, correlation‐coefficients (r) have been worked out for three‐hour periods, to determine whether the high degree of correlation found for twelve‐hour periods obtained during different parts of the night. In the following summary of results IA and IM are mean auroral intensity and magnetic character‐number, respectively.The correlation is good for all except the morning hours 3h to 6h. During these hours magnetic activity decreases more rapidly than auroral activity» The value of IA for the morning hours is as great as for the evening hours 18h to 21h, when conditions for observation of aurora are the same. It appears then that at this station, although auroral and magnetic activities are strongly associated during the greater part of the night, auroral activity continues into the morning hours when much quieter magnetic conditions prevail.