bluuebunny/crossref_metadata_2025 huggingface dataset:
Note on a graphical method of computing diurnal variations by differential formula
Authors: Duvall C. R. , Ennis C. C.
Published: February 2008

A graphical method is described which offers considerable advantages in simplicity, ease of construction, and facility of use for the determination of an unknown quantity which is related to two observed quantities by a formula of the general type p = ax + by. A particular application discussed is that in the reduction of magnetograph data at observatories.
Principal magnetic storms recorded at the Huancayo Magnetic Observatory, July to December, 1925
Authors: Booth R. T.
Published: February 2008

(Latitude, 12° 02.′7S.; Longitude, 75° 20′.4W. or 5h 01m.W. of Greenwich.)

During the quarter ending September 30, 1925, the only marked magnetic storm was the sudden commencement at 2h 17m September 20, 1925, in which the horizontal intensity increased about 92γ within the space of a minute or two and the vertical intensity and declination showed corresponding sudden commencements.
Erdmagnetische beobachtungen an der Winterstation des Gauss, 1902–03
Authors: Bartels Julius
Published: February 2008

1. Einrichtung und Betrieb der Station.—Die deutsche Südpolar‐Expedition auf dem Schiffe Gauss, unter der Leitung von E. von Drygalski, war vom 22. Febr. 1902—8. Febr. 1903 unter 60° 2′ südl. Breite und 89° 38′ östl. Länge v. Greenw., 385 m. über dem Meeresboden, 85 Km. von der Küste entfernt, vom Eise eingeschlossen. Durch eigenartige Verhältnisse war das Eisfeld auf dem Schelf des antarktischen Kontinents fast vollständig fest verankert, sodass es, wenn auch unter erheblichen Schwierigkeiten, dem Physiker der Expedition, Fr. Bidlingmaier2, möglich war, ein vollständiges magnetisches Observatorium 10 Monate (April 1902—Januar 1903) in vollem Betrieb zu erhalten.
Principal magnetic storms and earthquakes at the Watheroo Magnetic Observatory, October to December 1925
Authors: Johnston H. F.
Published: February 2008

(Lat., 30° 19′.1S.; Long., 115° 52′.6 or 7h 44mE. of Greenwich.)

October 21‐25, 1925. This protracted disturbance of moderate severity is the only one tabulated as a magnetic storm during October though the month as a whole was greatly disturbed. The storm was characterized by bays and peaks, the most prominent of which occurred on October 21 at 14h. 2 and 19h. 8, on October 22 at 14h. 5 and 19h. 7, and on October 24 at 8h. 2. At 8h on October 24 there was quite a violent disturbance in vertical intensity, causing a change of 80γ in 17 minutes; the disturbance in horizontal intensity was not marked, and the declination changed 13′ westward in the same period.
Principal magnetic storms recorded at the Huancayo Magnetic Observatory for January to March, 1926
Authors: Goddard Richard H.
Published: February 2008

(Latitude, 12° 02′.7S.; longitude, 75° 20′.4W or 5h 01m W. of Greenwich.)

January 13, 1926. This is not strictly a magnetic storm. There are two sudden commencements of interest. The first began at 19h 40m and in ten minutes the H trace had dropped 71γ. There followed a period of normalcy and at 20h 39m another sudden commencement in which the H decreased 85γ in twelve minutes, when it left the sheet and apparently continued its abrupt downward movement for some minutes, returning to registration approximately 30 minutes after leaving the sheet.
Ueber die Ursache der Schwankungen des luftelektrischen Potentialgefaelles
Authors: Gockel Von A.
Published: February 2008

Inhaltsangabe.—In einer früheren Arbeit hat der Verfasser die Frage untersucht, ob der Zusammenhang zwischen Sonnentätigkeit und den Aenderungen des elektrischen Erdfeldes ein direkter sein kann, vermittelt durch eine von der Sonne ausgehende Strahlung oder ein indirekter hervorgerufen dadurch, dass die Sonnenflecken die meteorologischen Faktoren und damit die Leitfähigkeit der Atmosphäre ändern. Die erstere Auffassung scheint die wahrscheinlichere.

Der Potentialgradient hängt ab von 2 unabhängigen Variabein, dem Luft‐Erdstrom und der Leitfähigkeit. Der erstere ist durch kosmische, die letztere durch meteorologische Faktoren beeinflusst. Wo sich die Leitfähigkeit der Atmosphäre wenig ändert, folgt der Verlauf des P. G. dem des Stromes. Dieser hat eine regelnlässige tägliche, jährliche und säkulare Schwankung. Der Zusammenhang tritt am deutlichsten hervor in der Arktis, der Antarktis und auf den Ozeanen. An andern Orten, an denen die Leitfähigkeit stark schwankt, wird der Verlauf des Luft‐Erdestromes ein unregelmässiger. Die 24 Stundenwelle des Potentialgradienten ist hauptsächlich durch den kosmischen Faktor beeinflusst, der sich nach Universalzeit ändert; die 12‐stündige durch Aenderungen der Leitfähigkeit, also meteorologische Vorgänge, die von der Lokalzeit abhängen.

Abstract.—In a previous paper the author investigated the problem whether the relation existing between solar activity and variations of the Earth's electric field, caused by radiation proceeding from the Sun, is a direct relation or whether, because of the fact that sunspots produce changes in meteorological factors which in turn affect the conductivity of the atmosphere, the relation is an indirect one. It would appear that the former assumption is the more probable.

The potential gradient depends upon two independent variables, the airearth current and the conductivity. The former is influenced by cosmic factors and the latter by meteorological. In the event where the conductivity of the atmosphere varies little, the course of the potential gradient follows that of the current. This current has a regular diurnal and annual variation and changes in the course of a sunspot cycle. This relation is most clearly evident in the Arctic and Antarctic regions and on Oceans. In other places where the conductivity varies strongly, the course of the air‐earth current becomes irregular. The 24‐hour wave of the potential gradient is influenced chiefly by the cosmic factor; this factor varies with universal time. The 12‐hour wave is caused by the variations of the conductivity and also of other meteorological occurrences which are dependent on local time.
Direct scaling of absolute magnetic values
Authors: McFarland W. N.
Published: February 2008

The operation of a magnetic observatory has for its object the eventual tabulation of the results in some form which will be convenient for the purposes of the investigator. The successful operation of the magnetograph, however, by no means completes the labor necessary for the attainment of this end. Several routine processes have to be maintained in order that the resulting records may be controlled, including absolute observations of the magnetic elements, and the determination of scale values of the magnetogram, all of which must be done at regular intervals.

The computer's work begins after the magnetogram has been developed and dried. The adjustment of the base‐line and scale‐value observations, while basic for proper carrying out of the rest of the program, is not long or laborious, but the measurement of the magnetograms and the subsequent reduction to the final absolute values which are printed, while simple in method, is both laborious and monotonous on account of the large number of operations of the same character which must be completed before the final values are obtained.
Micromagnetic oscillations as observed at the magnetical section of the Observatory of Irkutsk (Zouy), 1925
Authors: Pödder Arnold
Published: February 2008

Sensitive magnetographs reveal frequently on disturbed, as on quite calm, days waves of a peculiar type, which are characterized by their small period and which are not perceptibly connected with the Sun's activity. Some days they are very weak, but on other days their amplitudes reach very considerable values.

From the data of the special records of the Eschenhagen magnetograph at Zouy it can be concluded that two very different types of these waves exist:

Type I.—Very regular periodical vibrations of the magnet continuing over many hours or even days; the periods are well defined and vary in the limits of from 5 to 14 seconds approximately;

Type II.—Comparatively irregular vibrations having, however, a pronounced periodical character with considerably longer periods of a mean value of 34 seconds.
Swinging ship for the precise determination of deviations in magnetically‐disturbed harbors
Authors: Peters William J.
Published: February 2008

In the ordinary method of swinging ship, the vessel is held on the selected headings successively as for example, E, SE, S, SW, W, NW, N, and NE and on the swing with the other helm the order is reversed, NE, N, NW, W, SW, S, SE, and E. When the region is magnetically disturbed and the highest precision is sought there are two points to be considered.

a. In making a swing under ideal working conditions, that is perfectly calm weather, absolutely smooth water, with no current, and spending the same amount of time at uniform speed on each heading the vessel's course throughout the swing will describe a regular polygon as in Figure 1 in which the vessel on port swing, heads E from D to E, SE from E to F, etc., and on the starboard helm NW from F to E and W from E to D, etc. If the swings with both helms are made under these ideal conditions at the same speed and spending the same amount of time on each heading, the vessel will pass over the same bottom on opposite headings of the two swings, and the results for any two opposite headings of the two swings would be strictly comparable as regards irregular distribution of the local disturbance. This statement would not, however, hold for any other headings.
Considerations on measures for magnetic activity
Authors: Weinberg Boris
Published: February 2008

I would like to point out at first that the very name “magnetic activity” is ill chosen because there is no doubt that the aperiodic magnetic variations are due to some agency differing from terrestrial magnetism itself, for instance, to changes in Earth's currents or to atmospheric‐electric currents, or to currents of electrons emitted by the Sun, etc. Therefore from the physical standpoint we must try to find a measure for the intensity, A, of this very agency, its mean value Ā being the real cause of the variability of magnetic force, for instance, the agency being some current it is the intensity of the current.

If we do not wish to be influenced by the words it would be more adequate to speak about magnetic variability, but not about magnetic activity, reserving the word activity for the action of the agency causing these phenomena. This activity being beyond our means of observation we are obliged to estimate its amount according to the variations of the observed values of magnetic element at a number of stations.
The diurnal variation of the normal earth‐current in southern Sweden
Authors: Stenquist David
Published: February 2008

Since the month of August, 1924, measurements of earth‐currents have been made at the telegraph office of Lund (latitude 55°42′N, longitude 13°11′E) with a recording instrument. In another paper (Etude des courants telluriques, Mémoires publiés par la Direction Générale des Télégraphes de Suède, Stockholm, 1925) I have published the results of the recording of the first months (p. 21). On account of a miscalculation, the values on pages 21–23 of that paper are ten times too great. This unfortunate miscalculation has, however, no influence on the appearance of the chart on p. 25.
Watheroo Magnetic Observatory July, 1928
Authors: Johnston H. F.
Published: February 2008

(Latitude 30° 19′.1 S.; longitude 115° 52′.6 or 7h 44m E. of Gr.)

July 7, 1928—This was a severe magnetic storm. Between 22h and 23h (G.M.T.) on July 7 the magnetic elements began to depart markedly from the normal curve, and within an hour all three elements showed large and rapid fluctuations. From 23h.5 on July 7 to 7h on the following day was the period of greatest severity of the storm, the oscillations of all three elements being so rapid as to scarcely leave a record on the photographic trace. The declination was especially disturbed and the H‐trace was greatly depressed during the last half of the period.
On the diamagnetic field of the outer atmosphere
Authors: Chapman S.
Published: February 2008

The magnetic field of the diamagnetic layer in the outer atmosphere, to which R. Gunn has recently drawn attention, is examined, and shown to be remarkably similar to that of the daily magnetic variations.
Magnetic storms observed by the international polar expeditions 1882–1883
Authors: Bastamoff S.
Published: February 2008

Magnetic disturbances have been under investigation for many years. Recent expeditions, equipped with the most accurate instruments, have disclosed much that is characteristic of these phenomena. However, an examination of the earlier observations of terrestrial magnetism can furnish interesting material and particularly fruitful in this respect are the investigations of 1882–1883, for this was the only instance in the history of such researches that general and special observations were made in a complete network of stations surrounding the north magnetic pole and in its vicinity.

For these stations there were no self‐recording magnetographs. The instrumental precision was not great and there were other deficiencies. Still the published material is vast and may serve as an inexhaustible source for conclusions and generalizations. Up to the present time only a partial study of this material has been made and the final results of the gigantic enterprise have not yet been attained, because of the large scale of the undertaking. In the present paper several results are considered which I regard, on the basis of hourly magnetic observations, as belonging preponderantly to the so‐called magnetic storms.
Huancayo Magnetic Observatory, October, 1928
Authors: Ledig Paul G.
Published: February 2008

October 18, 1928—A violent magnetic storm began suddenly on October 18 at 7h 24m with an increase of 71γ in 3 minutes in horizontal intensity, and a marked increase in vertical intensity and decrease in declination. The horizontal intensity reached its maximum at 16h 09m and its minimum at 8h 38mon October 18, and during the whole period from the beginning of the storm to the end of the day showed large and rapid fluctuations with sharp peaks and deep bays. The most rapid change was a decrease of 153γ in four minutes, beginning at 8h 34m. The vertical intensity and declination were also severely disturbed, giving a marked saw‐tooth trace for both. After 23h 12m on October 18 the disturbance moderated greatly and ended at approximately 4h on October 19, although there were several hours of subnormal horizontal intensity.
Preliminary note on the origin of the permanent magnetic fields of the Sun and Earth
Authors: Gunn Ross
Published: February 2008

The writer's studies of the effects produced by ions as they are caused to execute long free‐paths and spiral about an impressed magnetic field by thermal agitation have led to interesting conclusions regarding the magnetic condition of the Sun and Earth. Such long free‐path phenomena take place only in the rarified atmosphere of the bodies. A calculation of the currents flowing in the atmosphere of the Sun and Earth as‐a result of an observed radial inhomogeneity in the magnetic field shows that the currents are inadequate to account for the observed magnetic moments, even though they flow in the correct direction.

A further study of the effects produced by ions moving under thermal agitation in a magnetic field and executing short free‐paths has led to a group of phenomena which are of great interest in the problem of the origin of the magnetic fields of the Sun and Earth. Ion‐drifts which can give rise to currents have been found to result under the following conditions: (a) When a magnetic gradient exists which has a component perpendicular to the impressed magnetic field; (b) when an electric or gravitational field exists which has a component perpendicular to the impressed magnetic field. In each case the direction of the ion‐drift is at right‐angles to both the magnetic field and the gradient.
The mobility‐spectrum of atmospheric ions—principles of measurements and results
Authors: Israël H. , Schulz L.
Published: February 2008

In the first part of the work, the methods of determining the “ionic spectrum,” that is, the percentage‐distribution of the ions for different mobilities, are discussed. The principle of the measurements consists in obtaining a current‐potential characteristic of a condenser through which air containing ions is passed. The ionic spectrum is obtained by forming a second differential quotient of the characteristic. Three different methods are described and their “resolving‐power” is discussed: The double‐condenser method, the method of the subdivided condenser, and the analysis according to Benndorf.

In the second part the ionic spectra as determined to date at twelve different stations are assembled. Since the revolving‐power of the double‐condenser method is limited, only four rather large mobility‐regions are at present differentiated. Apart from very large local differences, which cannot yet be cleared up individually, there appears an annual variation in the composition of the spectra, such that the spectral center of gravity lies at the smaller mobilities in winter and at the larger in summer. Increase of humidity has obviously the effect of enlarging the ions or of diminishing their mobility through the accretion of water‐vapor by them. A consideration of the separate representative mobilities of the various spectra shows that these are related as 1 : 2 : 3 or 1 : 2 : 4. This simple relationship suggests that perhaps the ions are of equal size but with one, two, or more elementary charges.
RECENT RESEARCHES ON FLUCTUATIONS OF COSMIC‐RAY IONIZATION
Authors: Broxon James W.
Published: February 2008

During the period since the detection of a natural, very penetrating, go‐called cosmic radiation soon after the discovery of radioactivity, there have been many investigations of the fluctuations of the ionization produced presumably by this radiation. In general, these have not been of an exhaustive nature, and throughout the history of the investigations the results have been conflicting in many details. In particular, there has not been general agreement regarding the peculiarly interesting question as to whether the fluctuations provide evidence of regular variations of the penetrating‐radiation intensity with time. At present there appears a tendency toward the conclusion that such variations, if they exist, are very small and perhaps produced by terrestrial conditions.
SOME PRACTICAL ASPECTS OF THE THEORY OF THE UNIFILAR HORIZONTAL‐INTENSITY VARIOMETER
Authors: Forbush S. E.
Published: February 2008

The condition for stable equilibrium of a horizontal‐intensity variometer, without control‐magnets, is derived from the potential energy of the system. It is then shown that for quite sensitive variometers the equilibrium may, for a properly adjusted instrument, become unstable for subnormal values of horizontal intensity which occur during magnetic storms. The effect of temperature‐compensation magnets on stability is treated. The scale‐value equation is developed and it is shown that the factor which represents the change of scale‐value with ordinate may be obtained directly from the value of the horizontal intensity at the instrument, and the optical lever. Tables indicate for three different instruments at widely different locations the agreement between the values calculated in this way and those obtained from the usual adjustment of observed scale‐values. Finally, the effects of a control‐magnet upon the conditions for stable equilibrium and upon the scale‐value equation are investigated. The possibility of using a control‐magnet to decrease temporarily the sensitivity of the instrument during severe magnetic disturbances is suggested. Some discrepancies between the scale‐value equations derived in this note and those obtained by George Hartnell in his treatise on “Horizontal‐intensity variometers” are indicated and explained.
ON THE POSSIBILITIES OF A TIDAL EFFECT IN THE KENNELLY‐HEAVISIDE LAYER AS EVIDENCED BY AN APPARENT CORRELATION OF THE INTENSITY OF RADIO RECEPTION WITH POSITIONS OF THE MOON
Authors: Stetson Harlan T. , Johnson Josef J.
Published: February 2008

Previous papers1 have pointed out the probable existence of a correlation between the intensity of radio reception and the Moon's position in the observer's sky at the time the intensity‐measurements are made. Corroborating evidence has come from subsequent investigations by Pickard2 and by Kenrick and Pickard,3 as to the reality of the lunar effect. The variation in intensity considered implies a rise and fall in the Kennelly‐Heaviside Layer, or an equivalent change in the electrondensity of the ionosphere, which assumes the appearance of an electronic tide. It was pointed out in the first paper mentioned that such might be caused either by the Moon's gravitational effect on the upper atmospheric layers or by some unknown effect of the Moon acting as an ionizing agent, such, for example, as would be the case were the Moon to possess an appreciable electrostatic charge.
PROVISIONAL SUNSPOT‐NUMBERS FOR MARCH TO MAY, 1934
Authors: Brunner W.
Published: February 2008

(Dependent alone on observation at Zürich Observatory and its station at Arosa)
PROVISIONAL SOLAR AND MAGNETIC CHARACTER‐FIGURES, MOUNT WILSON OBSERVATORY, JANUARY, FEBRUARY, AND MARCH, 1934
Authors: Nicholson Seth B. , Sternberg Elizabeth E.
Published: February 2008

The diurnal range in H at Mount Wilson exceeded 100y on February 9, February 16, and March 5, but the variations on these days were not classed as magnetic storms.

Thirteen spot‐groups were observed in the first quarter of 1934, five belonging to the waning cycle and eight to the new cycle. The increasing activity of the new cycle in the high solar latitudes indicates that the phase of minimum activity is probably past.
HUANCAYO MAGNETIC OBSERVATORY JANUARY TO MARCH, 1934
Authors: Cairns J. E. I.
Published: February 2008

(Latitude 12° 02′.7 S.; longitude, 75° 20′.4 or 5h 01m W. of Gr.)

March 4‐8—A disturbance, which lasted from March 4 to 8, was not of a very marked nature, the principal characteristic being the rapid oscillatory‐motions of relatively small amplitude. The disturbance began quietly on March 4 at 10h 20m G.M.T., with oscillations of small amplitude. As the maximum was approached at 14h the violence of the motions increased but not so strongly as not to record. The normal minimum was reached by a succession of descending bays at 21h 27m March 4 and was lower than usual. Disturbed conditions, the principal characteristics of which were lowered ordinates and oscillatory‐motions, particularly around the time of maximum and minimum, then persisted until March 7. The maximum of March 7 was considerably flattened and the minimum thereby obscured.
Sur quelques erreurs systématiques d'une balance magnétique
Authors: Olsen Johannes
Published: February 2008

Résumé—La note ci‐après est une analyse d'une balance magnétique dont l'axe de rotation et l'axe magnétique ne sont pas horizontaux. Il y est montré que les erreurs qui en suivent, ont pour effet que la marche diurne de la déclinaison et celle de l'intensité de la force horizontale déforment l'enregistrement de la marche diurne de l'intensité de la force verticale. On déduit des formules pour la réduction des sources d'erreur en question.
Critical‐frequency observations of the E‐layer at the Huancayo Magnetic Observatory
Authors: Wells H. W.
Published: February 2008

This paper describes the nature and characteristics of the reflections from the E‐layer of the ionosphere as observed at the Huancayo Magnetic Observatory, and gives a comparison of the results obtained with similar investigations in the higher latitudes.

It is shown that no marked critical frequencies are in evidence, and that the transition from the E‐region to an upper ionized layer, or vice versa, is a gradual process with little evidence of the long retardations which are frequently observed in the higher latitudes. There is, however, a definite and smooth diurnal variation of estimated maximum ionization which peaks around noon. The results indicate that the refractive index of the electromagnetic waves returned from the region of the maximum ionization of the E‐layer is complex and that dissipation is appreciable. Epstein's conclusion, that if the collisional frequency is large, part of the energy will be reflected and part transmitted, is borne out by these observations. It may be noted that this appears to be the necessary condition for the qualitative fulfilment of the so‐called “atmospheric‐dynamo” theory of diurnal variation of the Earth's magnetic field.
Observed relative sunspot‐numbers, 1749–1933
Authors: Sternwarte Eidgenössische
Published: February 2008

Editor's note—In view of the numerous requests received for the final values of measures of solar activity and the depletion of the supply of reprints of the table of observed relative sunspot‐numbers for 1749 to 1924 published in this JOURNAL (30, 83–86, 1925), the table of final observed relative sunspot‐numbers is reprinted above with additions through the year 1933. For detailed accounts of the derivation of these numbers the interested reader may be referred to the various issues of the Astronomische Mitteilungen, begun by Wolf and continued by Wolf and Brunner. It has seemed desirable also to extract in Tables 2 and 3 the values of relative sunspot‐numbers applying for the central zone only and the values of intensity of ultra‐violet radiation so far as these have been observed. Tables 2 and 3 are extracted from the “Bulletin for character‐figures of solar phenomena” of the International Astronomical Union published by the Swiss Federal Observatory in Zürich.
The magnetic character of the year 1933 and the numerical magnetic character of days, 1933
Authors: van Dijk G.
Published: February 2008

The annual review of the “Caractère magnétique de chaque jour” for 1933 has been drawn up in the same manner as for preceding years. Forty‐nine observatories contributed to the quarterly tables, forty‐eight of them sent complete data.

Table II (reproduced as Table 1 below) of the annual review, contains the mean character of each day for each month. The lists of calm days and disturbed days, and the days recommended for reproduction are also reprinted here as Table 2.
Sitka Magnetic Observatory, April to June 1934
Authors: Hershberger John
Published: February 2008

(Latitude 57° 03′.0 N., longitude, 135° 20′.1 or 9h 01m.3 W. of Gr.)
Watheroo Magnetic Observatory, April to June 1934
Authors: Parkinson W. C.
Published: February 2008

(Latitude 30° 19′.1 S., longitude, 115° 52′.6 or 7h 43m.5 E. of Gr.)
Summary of some auroral height‐measurements and observations at Chesterfield, Canada
Authors: Currie B. W.
Published: February 2008

The Aurora‐Borealis investigations of the Canadian International Polar‐Year party located at Chesterfield Inlet, (63° 20′ north, 90° 42′ west), comprised single‐station visual observations, single‐station photographs of the brighter displays, and double‐station photographs for height‐measurements. To date height‐measurements have been made on 200 of the parallactic photographs, and a study has been made of the visual observations on nights without cloud.

The secondary auroral station was located south of Chesterfield on the coast of Hudson Bay. It was established during September, 1932, when it was possible to travel along the coast by boat. A sod shelter, Figure 1, was built, and a supply of food and kerosene left there for future use. The position of this station relative to the Chesterfield station was determined the following spring by triangulation and stadia‐rod surveys over the Bay ice. The values obtained were: Length of base‐line, 33.14 km; azimuth from north, +173° 39′.
Seasonal variation in Earth‐currents at Tucson, Arizona
Authors: Rooney W. J.
Published: February 2008

The seasonal changes in earth‐current flow at Tucson, Arizona, have been determined from a study of the calm day diurnal‐variation records for the three‐year period 1932–34 obtained through the cooperation of the Department of Terrestrial Magnetism of the Carnegie Institution of Washington, the United States Coast and Geodetic Survey, the American Telephone and Telegraph Company, and the Mountain States Telephone and Telegraph Company. The records are of unusual interest because of the location of Tucson in the transition‐belt where the diurnal variation of magnetic dip and intensity change from high‐latitude to equatorial type. The diurnal variation in earth‐current potential‐gradient, as shown by a series of monthly hodographs also changes radically with season. During the winter the hodographs are nearly circular with the current‐vector proceeding in two clockwise loops. During the summer they are elongated greatly along a line which corresponds closely to the magnetic meridian and the clockwise rotation of the vector tends to disappear at midday. A decided parallelism with the changes noted in the diurnal variation of the magnetic elements as recorded at the same station adds to the evidence linking the two phenomena together.
Provisional sunspot‐numbers for June to August, 1935
Authors: Brunner W.
Published: February 2008

(Dependent alone on observation at Zürich Observatory and its station at Arosa)
Watheroo Magnetic Observatory April to June, 1935
Authors: Parkinson W. C.
Published: February 2008

(Latitude 30° 19′.1 S., longitude 115° 52′.6 or 7h 43m.5 E. of Gr.)

May 1–2—This moderate disturbance began May 1 at 12h 47m, G. M. T., with a sudden commencement. Horizontal intensity increased 15 gammas in five minutes, vertical intensity decreased five gammas, and declination 0′.5 in the same interval. The disturbance ended May 2 at approximately 2h.
A solar eruption on November 6, 1936, and disturbances in Earth's magnetism, Earth‐currents, and the ionospheric regions
Authors: Torreson O. W. , Davies F. T. , Scott W. E. , Stanton H. E.
Published: February 2008

Spectrohelioscope‐observations—During the usual observing period of 15:30 to 16:00 GMT, some small prominences on the Sun were seen to undergo minor changes, but there was no activity noted at or near the various spots present. While members of the staff were inspecting the earth‐current recorder at approximately 16:15, it was noted that a sudden change in earth‐current potentials had occurred shortly after 16:00, and it was decided to inspect the solar disc immediately, although the next regular period of solar observation was not to commence until 16:30. There was found at 16:24 a quite brilliant sunspot located at approximately 17° south and 37° west, oval in shape, though somewhat irregular at various points on the periphery. By 16:40 the intensity had decreased to about one‐half of that at 16:24, and by 16:50 the spot had faded completely to the same intensity as the other nearby spots and was quite indefinite in shape. On the basis of the adopted scale of “importance” of solar eruptions, this may be said to have been of “importance 1 to 2.” It appeared quite probable that the eruption had been in progress some minutes prior to 16:24.
Sudden ionospheric disturbances
Authors: Dellinger J. H.
Published: February 2008

This paper presents a summary of the data and conclusions up to this time of an investigation, started about the middle of 1935, of a comparatively new phenomenon. The phenomenon is the occurrence of a sudden intense increase in the ionization of a portion of the ionosphere, with resultant transient disturbances in such phenomena as radio‐wave transmission, terrestrial magnetism, and earth‐currents. The effects last for a period ranging from a few minutes to an hour or more. The whole phenomenon is of scientific interest particularly because it appears to have its origin in sudden bursts of radiation from the Sun, and is opening the way to increased understanding of the Sun, the ionosphere, radio transmission, terrestrial magnetism, and related phenomena.
The fundamental theorem of applied geophysics
Authors: Löwy H.
Published: February 2008

In all methods of geophysical prospecting, the attempt is made to ascertain the depth and extent of deposits (ore, oil, ground‐water) by means of certain measurements made on the Earth's surface. The question as to whether and under what conditions such an analysis may be made in a unique manner constitutes the fundamental problem of applied geophysics.

The problem requires a separate solution for each method. In 1927, I published a solution for the electrodynamical method. As for the other geophysical methods, in the absence of a solution, recourse is had to a rule formulated by Professor A. O. Rankine as follows: “Underground structures, agreeable to the geophysicist's experience, have to be taken as hypotheses, and tested by calculation and comparison with the data provided by surface‐observations.” It is a very laborious and uncertain procedure. Even if one, by good luck, succeeds in divining a hypothetical underground structure which is in ideal agreement as respects the calculated and observed values, yet there is no certainty that this corresponds with reality. The physical values at the surface are uniquely determined by the underground structure but the inverse theorem—namely, that the underground structure may be uniquely ascertained from physical measurements made at the surface—does not necessarily follow. Indeed, it is not upon physics nor upon mathematics (however imposing some of the displays of the latter) but upon geology that the successful interpretation of geophysical measurements usually depends. The hypothetical structure must be “agreeable to the geologist's experience.” This is, according to Rankine “the geologist's selection rule.” It signifies no guide in the terra incognita, but, on the contrary, the exclusion of it. Until the fundamental problem is solved, the geophysicist will be obliged to work only in geologically known country.
The American character‐figure CA as a measure of magnetic activity of the Earth
Authors: McNish A. G. , Ludy A. K.
Published: February 2008

A close relationship between radio‐transmission conditions and irregular fluctuations of the Earth's magnetic field has been recognized for some time. The nature of this relationship may be briefly stated as follows: At times when the variations of the Earth's magnetism are of a regular character transmission over long distances is generally good on all frequencies, but when the variations are irregular—that is, during magnetic “storms”—communication over high‐latitude paths is unsatisfactory or altogether impossible on the higher frequencies.

In efforts to understand this relationship better, numerous investigators have made correlations of radio conditions and magnetic storminess. Various measures of storminess have been used—sometimes the daily range of magnetic change at a single station, sometimes a subjective estimate of storminess as assigned by the observer‐in‐charge of a magnetic station. Such measures are not fully adequate as they only partially represent the conditions at a single point on the Earth. Magnetic storms affect the entire Earth although local conditions may vary considerably.
On the lunar‐diurnal variation in the earth‐currents
Authors: Egedal J.
Published: February 2008

In examining earth‐potentials at Jersey Marc Dechevrens twenty years ago found variations of tidal type, and in examining ordinary earth‐current observations the author demonstrated a lunar influence on the earth‐current potential‐gradient at Ebro, Spain, for the hours 10 to 11 a.m. In the following a complete determination of the lunar‐diurnal variation of the earth‐current potential‐gradient will be mentioned and discussed.

The observational data—The data used for the present determination of the lunar‐diurnal variation of the earth‐current potential‐gradient are taken from the earth‐current observations made at Ebro in the period January 1 to December 21, 1910 (12 lunations). Only the data designated N→S, giving the potential‐gradient in a direction 25° west of north, have been examined.
Provisional sunspot‐numbers for March to May, 1937
Authors: Brunner W.
Published: February 2008

(Dependent alone on observation at Zürich Observatory and its station at Arosa)
The unusual aurora of March 30, 1937
Authors: Harradon H. D.
Published: February 2008

On the night of March 30, 1937, a remarkable auroral display was visible over a large part of North America.

Dr. E. H. Bramhall, of the University of Alaska, describes the phenomenon as observed by him at College, Alaska, as follows: “The unusual feature of the aurora was the blood‐red glow of considerable intensity. At 22h 45m, March 30, 150° west meridian time (8h45m GMT, March 31), I observed such a glow in the area from east to 20° south of east, and from the horizon to 20° altitude simultaneously with active rayed bands of unusual color in the same region and in the south and west. In the zenith there remained a partial corona with intense bands towards east and northwest; in fact in all parts of the sky except due north there was evident some activity. At 23h (9h GMT, March 31) a similar blood‐red glow developed in the south in the region of a very active rayed band. At 23h 10m (9h 10m GMT, March 31) the red was only faintly visible although the activity in all directions was still great.”
Aurora of April 25 to 29, 1937, at Shawinigan Falls, Canada
Authors: Germain Leo
Published: February 2008

The following observations were taken in my home town, Shawinigan Falls, which is about half‐way between Montreal and Quebec City, Canada.

At the period of the reported magnetic storms, April 25 to April 29, 1937, we were more fortunate than people further south for we could observe the finest display of the Aurora Borealis. It covered half the sky; we could see this light in the east and west as well as in the northern sky, and directly overhead. On one of the nights it extended south to about 20° from the zenith. The light seemed as strong directly overhead as it was towards the north. Looking directly upward, the rays appeared like strong streaks of light falling on us in a shower and slightly bent toward the north. On the night of May 9 I noticed again the same phenomenon and radio reception was rather poor, even from station CKAC, a 5000‐watt station 80 miles away which is usually heard clearly.
International catalogue of magnetic determinations
Authors: Weinberg Boris
Published: February 2008

Having received no reply to my proposal regarding the publication of the international catalogue of magnetic determinations (Union Géod. Géophys. Internat., Ass. Mag. Electr. Terr., Bull. No. 9, 260–263, 1934), it was decided to collect and summarize, if possible, all the results of magnetic determinations accessible to us. On the assumption that the magnetic charts from the middle of the last century furnish a trustworthy representation of contemporary observations, we have not collected determinations subsequent to 1825. We have utilized the following sources:
Sitka Magnetic Observatory January to March, 1937
Authors: Hershberger John
Published: February 2008

(Latitude 57° 03′.0 N., longitude 135° 20′.1 or 9h 01m.3 W. of Gr.)

February 2–4—A disturbance beginning sharply at 23h 04m GMT, February 2, continued with small but gradually increasing amplitudes for a number of hours, reaching its maximum intensity a few minutes after 07h February 3. At this time the horizontal intensity, which had increased approximately 400 gammas since the beginning of the disturbance, rapidly decreased about 750 gammas, returning in about a half‐hour to a little above its normal value. The other two elements took similar, though smaller, excursions at the same time, the vertical intensity decreasing and east declination increasing. Within a few hours the oscillations had nearly died out, but became more violent again from about 16h to 22h. Thereafter the storm gradually died away, ending at about 01h, February 4.
Cheltenham Magnetic Observatory January to March, 1937
Authors: Ludy Albert K.
Published: February 2008

(Latitude 38° 44′.0 N., longitude 76° 50′.5 or 5h 07m.4 W. of Gr.)

January 27–28—A sudden commencement of a disturbance began at 08h 38m GMT, January 27, after a very quiet period. The disturbance lasted about 20 hours and was characterized by short‐period perturbations of small amplitude. At the beginning of the disturbance the horizontal intensity decreased 4 gammas, followed by an abrupt increase of 40 gammas. The changes in declination and vertical intensity were small but noticeable.
Tucson Magnetic Observatory January to March, 1937
Authors: Joyce J. Wallace
Published: February 2008

(Latitude 32° 14′.8 N., longitude 110° 50′.1 or 7h 23m.3 W. of Gr.)

February 2–4—A severe disturbance, beginning with sudden commencements in all three elements at 23h 04 GMT, February 2, was characterized by short‐ and moderate‐period activity, particularly in D and H, superimposed on two long‐period bays. The storm ended at about 02h GMT, February 4. Ranges were: H, 195 gammas; Z, 46 gammas; D, 16′.
Watheroo Magnetic Observatory January to April, 1937
Authors: Green J. W.
Published: February 2008

(Latitude 30° 19′.1 S., longitude 115° 52′.6 or 7h 43m.5 E. of Gr.)

January 27—There was a sudden commencement January 27 at 08h 36m 44H GMT, as shown by the record of the Crichton‐Mitchell vertical‐intensity inductometer. D moved 2′ eastward abruptly and swung back, sharply followed by a second movement of 2′ eastward during the next four minutes of time. H increased 25 gammas in three minutes with a further increase of 5 gammas in the next minute. The numerical value of Z decreased 9 gammas abruptly, followed by a further decrease of 16 gammas in five minutes. This disturbance of short duration had a range in H of 166 gammas, the ranges in D and Z being practically normal.
Chapters in the history of terrestrial magnetism
Authors: Mitchell A. Crichton
Published: February 2008

Chapter II—The discovery of the magnetic declination

1—In Chapter I it was shown that the compass had been brought into use in northwestern Europe for the purposes of navigation by the year 1187, that its first mention in the literature of that year does not refer to it as being of recent introduction, that the discovery of the directive property of a magnet in the Earth's field must have preceded this application by some considerable time, but that of this time it was not possible to frame any reliable estimate.
Further studies of radio fade‐outs
Authors: Berkner L. V. , Wells H. W.
Published: February 2008

Observations during a radio fade‐out by a comprehensive automatic multifrequency technique have yielded more detailed information concerning the nature of the effect. Data for the fade‐out of July 31, 1937, are presented and analyzed for possible effects in the several regions of the ionosphere. It is concluded that there is no evidence of change in either the F1 or F2regions. A slight increase in virtual height and maximum ion‐density of the E‐region is apparent just after the fade‐out which is sufficient to account for the destruction in normal E‐region reflecting boundary previously described. The evidence indicates that the effect occurs primarily below the 100‐km level where the waves are absorbed because of an intense ionization in a region of high collisional frequency. Absorption of the ionization from the Sun responsible for the fade‐out must be negligibly small in the F1 and F2‐regions to account for the stability of these regions during the period of the fade‐out.
American URSI broadcasts of cosmic data, July to September, 1937, with American magnetic character‐figure CA, September to November, 1937
Authors: Johnston H. F.
Published: February 2008

The data for terrestrial magnetism, sunspots, and solar constant 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 Atmospheric 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 foot‐note 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 the mean value of k for Mount Wilson was 0.53 during 1936.
Annual variation of the critical frequencies of the ionized layers at Tromsø during 1937
Authors: Harang Leiv
Published: February 2008

Daily measurements of the critical frequencies, the results of which up to September 1936 are given in a previous paper1, were continued during 1937. Regular observations were usually taken on six days during the week at 10h, 12h, 14h, and 18h, local time. At Tromsø, a station subject to much magnetic disturbance, the echoes during disturbed periods appear very irregularly and are often lacking during the most intense phase of the Earth's magnetic or auroral activity. Figure 1 shows the variation of the critical frequencies for the F2−, F1−, and E‐layers during 1937.
A method for producing non‐magnetic castings of copper, brass, and aluminum
Authors: Steiner W. F.
Published: February 2008

A method of obtaining sound non‐magnetic castings for use in magnetic measurements has been developed. This is done by a close control of the melting temperatures, a method of purification of the metal, and design of the patterns.
Cheltenham Magnetic Observatory, January to March 1938
Authors: Ludy Albert K.
Published: February 2008

(Latitude 38° 44′.0 N., longitude 76° 50′.5 or 5h 07m.4 W. of Gr.)

January 12–13—A mild disturbance began about 22h GMT, January 12, and lasted until 16h, January 13. The oscillations were irregular with no outstanding features.
On the production of the ionospheric regions E and F and the lower‐altitude ionization causing radio fade‐outs
Authors: Wulf Oliver R. , Deming Lola S.
Published: February 2008

Recent observations of the reflection and absorption of radio waves have afforded much information regarding the behavior of the ionosphere during a radio fade‐out of the type occurring at the time of conspicuous outbursts in the chromosphere of the Sun. Berkner and Wells [see 1 under “References” at end of paper], using the automatic multifrequency technique, have studied the detailed behavior of the ionized layers during a fade‐out and find that conditions in the F1‐ and F2‐regions undergo essentially no change. In the E‐region a small increase in virtual height and maximum ion‐density seems to occur. After the E‐region conditions have returned to normal, abnormal absorption of the exploring radio waves is still observed, showing that absorption occurs below the maximum of the E‐region ionization.
Watheroo Magnetic Observatory July to September, 1938
Authors: Green J. W.
Published: February 2008

(Latitude 30° 19′.1 S., longitude 115° 52′.6 or 7h 43m.5 E. of Gr.)

July 9–10—A sudden commencement occurred at 19h 51m GMT, July 9. D, after a slight easterly movement, moved westerly 2′.0 in four minutes, H increased 14 gammas in five minutes, and Z, after a slight numerical increase, decreased 13 gammas in four minutes. Moderately disturbed conditions prevailed for 24 hours.