bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cheltenham Magnetic Observatory October to December, 1936
Authors: Ludy Albert K. 
Published: February 2008

(Latitude 38° 44′.0 N., longitude 76° 50′.5 or 5h 07m.4 W. of Gr.)October 9–10—A mild disturbance began about 7h 30m GMT, October 9. It continued until about 22h, October 10. The perturbations were irregular and not of great range. The more severe part of the storm was from 1h to 10h, October 10.
The long periodic variation in the diurnal range of magnetic horizontal component at Oslo Observatory
Authors: Wasserfall K. F. 
Published: February 2008

As is known Hansteen began in the year 1843, a series of daily variaatlon‐observations of the magnetic elements in Oslo, which have been continued uninterrupted to the present time. Some years ago the author undertook to compile the entire material left by Hansteen and his successors, pertaining to observations of the horizontal component.The material consists of two daily observations during 1843 to 1930; the readings were taken at 9h and at 14h local mean time. A large magnet, 1.2 meters long and weighing 13 kg is mounted by a bifilar suspension in the vault of the central hall of the Astronomical Observatory in Oslo. A small mirror, fixed to the magnet, reflects a divided scale mounted horizontally below a telescope which rests on a marble pier in the west wing of the building.
On the lunar‐diurnal variation in the Earth‐currents
Authors: Egedal J. 
Published: February 2008

In my article printed in this JOURNAL, June 1937 (pp. 179–181), the values given in Table 2 for the lunar variation of the earth‐current potential‐gradient during the solar hours 20 to 5 at Ebro Observatory for the year 1910 (direction 25° west of north) are to be corrected as follows:Hour Main term L2 in mv/km20 to 21 2.4 sin (2t+21°)22 to 23 2.4 sin (2t+7°)0 to 1 1.6 sin (2t+15°)2 to 3 1.2 sin (2t+355°)4 to 5 1.4 sin (2t+36°)The value of L2 for the hours 20 to 5 is L2 = 1.8 sin (2t+15°) mv/km and for the day‐hours 6 to 19 is L2 = 2.2 sin (2t+44°) mv/km. The amplitude of L2 for the night‐hours is only a little smaller than that for the day‐hours and the phase‐angles for the two periods are not much different. As the amplitudes of L2 for both night and day are of good accuracy, it is evident that the amplitudes mentioned are not much different and it might seem desirable to reconsider theories on earth‐currents and earth‐current measurements.
Natural residual magnetism of eruptive rocks
Authors: Koenigsberger J. G. 
Published: February 2008

§ 1. The apparatus for the measurement of remanence (Jrn, Jrs, Jrc) of magnetization JK and of susceptibility K of rocks [see sections “ Literature,” Part I and Part II] are of two kinds:(a) Magnetometers, chiefly astatic [I, 1926c and 1927a, b, etc.], some showing a weak field at the position where the sample is placed, with compensation of the deflection, which requires a regular shape of specimen in measuring remanence or susceptibility [I, 1930c]; the sample may be put in a coil with a known magnetic field to measure JK for different values of H [I, 1930a, p. 273].
The electric current‐system of geomagnetic disturbance
Authors: Vestine E. H. , Chapman S. 
Published: February 2008

I—IntroductionI. 1—This paper concerns the electric current‐system associated with the main systematic characteristics of geomagnetic disturbance or magnetic storms. The discussion continues that given previously in a sequence of papers by Chapman [see 1, 2, 3 of “References” at end of paper].
Huancayo Magnetic Observatory July to September, 1938
Authors: Davies Frank T. 
Published: February 2008

(Latitude 12° 02′.7 S., longitude 75° 20′.4 or 5h 01m.4 W. of Gr.)July 4–5—A sudden commencement occurred at 12h 03m GMT, July 4. In a period of three minutes D moved east 2′, H increased 28 gammas, and Z showed only a slight effect. Following this a magnetic storm continued until 06h, July 5. Ranges: D, 7′.9; H, 272 gammas; Z, 43 gammas.
Two new books on terrestrial magnetism and electricity: a review and a review
Authors: Chapman S. 
Published: February 2008

There has been published recently (August 1939) a volume on “Terrestrial magnetism and electricity” which is the latest and largest (778 pages) of a series 1 issued under the general title “The physics of the Earth.” All of them were prepared under the direction of committees of the National Research Council (U.S.A.); the first six volumes were published as Bulletins of that Council. The purpose underlying this scheme, initiated in 1926, was “to give to the reader, presumably a scientist but not a specialist in the subject, an idea of its present status together with a forward‐looking summary of its outstanding problems,” in view of the “considerable development of interest in geophysics, ... not. matched by the publication in English of systematic treatises on the subject” (Foreword).In terrestrial magnetism and electricty the lack of such a treatise has been, and is, a decided handicap to American and British workers in the subject; I hope that the present war will not prevent the expected publication, this year, of the treatise “Geomagnetism” which has been in preparation since 1927, in collaboration (since 1929) with J. Barrels. It seems appropriate, if unusual, to refer to this forthcoming treatise in the present review, and to make some comments on the relation in which the two books will stand to each other. Certainly if their success is at all commensurate with the long period (over a sunspot‐cycle!) occupied by their preparation, English‐speaking geophysicists and physicists will gain an altogether new ease of access to the hitherto somewhat veiled arcana of earth magnetism and electricity.
The three‐hour‐range index measuring geomagnetic activity
Authors: Bartels J. , Heck N. H. , Johnston H. F. 
Published: February 2008

Geomagnetic activity, the frequency and intensity of magnetic disturbance, is supposed to indicate the influence of solar corpuscular radiation on the Earth. Various schemes for measuring the fluctuations of this phenomenon are in operation, but in connection with direct ionospheric studies by radio methods it was found necessary to provide a new scheme using smaller time‐units than a day or half a day. A three‐hour‐range index K based on the “Potsdamer erdmagnetische Kennziffer” was therefore provisionally adopted by the International Association of Terrestrial Magnetism and Electricity, at Washington, D.C., U.S.A., in September 1939. Each collaborating observatory is to assign, to each three‐hour interval beginning at 0h, 3h, … etc. GMT, one of the integers 0 to 9 as range‐index K; their averages Km, carried to half‐units, express the new measure. Scales for K are determined by assimilation of frequency‐curves so that each observatory, within a year, for instance, has approximately the same number of intervals with K=0, or with K=1, etc. The principles and the practice of scaling K are described. The magnetic variations are regarded as superpositions of K‐variations (to be measured), and of non‐K‐variations (such as regular daily variations on quiet days, to be eliminated); this is illustrated by typical cases.For January to June 1938, tables for K and Km are given based on eight observatories. From Km, daily indices B for 24‐hour intervals are derived, also equivalent ranges A. High correlations are found between K at the different observatories and Km. The effect of the persistence‐tendencies on these and other correlations is studied and provides examples of general interest in statistics. In general, the correlation‐coefficient r increases with the length of the time‐unit used; for instance, for the daily index B and the international character‐figure C, r is 0.95 for single days, but it reaches 0.98 for four‐day averages.Incidentally, a geomagnetic solar‐flare effect was found preceding the outbreak of the intense storm on January 16, 1938; the time‐interval suggests 22 hours as an upper limit for the travel‐time of the solar corpuscles.
Analysis of local atmospheric‐electric phenomena at College, Alaska
Authors: Gish O. H. , Sherman K. L. 
Published: February 2008

The atmospheric‐electric data obtained at College, Alaska, during the International Polar Year have been analyzed in order (1) to separate the universal and local features in their diurnal variation and (2) to compare them with the theory of the electrode‐effect. After eliminating the universal diurnal‐variation component from the potential‐gradient a local component remains. In winter this local component is largely the result of variations in the conductivity near the Earth's surface but in summer there is no correlation between these elements. The calculated ratio of the columnar resistance of the air over College to that over the oceans shows a diurnal variation. The statistical significance of this variation is questioned. If it is significant various hypotheses which could account for such a variation are considered.The diurnal variation in positive conductivity retains its character throughout the year although its amplitude is about 50 per cent less in summer than in winter. Its variations are attributed chiefly to variations in q and N. In contrast the diurnal variation of negative conductivity changes markedly from summer to winter. The negative conductivity depends greatly on the field in winter whereas in summer the increased wind or factors closely associated with it effectively oppose the action of the field.The theory of the electrode‐effect is reviewed and amplified. Following the method of Scholz additional relations based on both the large‐ and small‐ion theory are developed so that a variety of conditions are covered. Some of the results are presented graphically for ease in comparing with these and other results. The air at College was very quiet in winter and apparently met this restriction of the theory for the results obtained then are shown to be in satisfactory quantitative agreement with the theory.
Three‐Hour‐Range Indices, K, For Twelve Magnetic Observatories, January to June, 1940
Authors: Johnston H. F. 
Published: February 2008

The Association of Terrestrial Magnetism and Electricity of the International Union of Geodesy and Geophysics passed a resolution in regard to three‐hour‐range indices at its Seventh Assembly held in Washington in September, 1939. The resolution was as follows: That the cooperation of magnetic observatories be sought for a three‐year period in an international trial‐scheme for the provision of three‐hour‐range indices (K) to characterize the variation in the degree of irregular magnetic activity throughout each day, especially in order to meet the requests made by the International Union of Scientific Radio telegraphy and other bodies for information concerning the magnetic activity more detailed than the present daily magnetic character‐figures, and that this trial‐scheme should, for the period 1940 to 1942, replace the scheme for a numerical character‐figure.In response to the circular letter of January 20, 1940, from Dr. J. A. Fleming, President of the Association of Terrestrial Magnetism and Electricity, 19 magnetic observatories are supplying indices beginning January 1, 1940. The indices from seven observatories for 1940 were published1 in the issue for March, 1941, of this Journal. Those from the other 12 observatories for the period January to June, 1940, appear herewith. The principles and practice of scaling K are described in the paper2 entitled “The three‐hour‐range index measuring geomagnetic activity.”
Three‐Hour‐Range Indices, K, for Twelve Magnetic Observatories, July to December, 1940, and Summary for 1940
Authors: Johnston H. F. 
Published: February 2008

K‐indices from 12 magnetic observatories for the second half of 1940 are published herewith. Those for the first half of 1940 were published1 in the issue for June, 1941, of this Journal and the indices from the seven American‐operated observatories for the year 1940 were published2 in the issue for March, 1941, of this Journal. In accordance with the wishes of Dr. J. Bartels, Director, Geophysikalisches Institut, Potsdam, who is Chairman of the Committee on Three‐Hour‐Range Index, the text of the circular letter of January 20, 1940, from Dr. J. A. Fleming, President of the International Association of Terrestrial Magnetism and Electricity, sent to all directors of magnetic observatories, is given as follows :“At its assembly at Washington in September 1939, the Association of Terrestrial Magnetism and Electricity adopted a resolution as follows:
The Ionosphere at Huancayo, Peru, April to June, 1941
Authors: Ledig P. G. , Coile R. C. , Jones M. W. 
Published: February 2008

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

April 24–26—A moderate storm began at 07h 10m GMT, April 24, with long‐period fluctuations. The major activity ended at 10h, Ap il 25, though small fluctuations continued until 11h, April 26. Ranges: D, 19′.5; H, 200 gammas.June 13–14—A moderate storm began abruptly at 03h 43m GMT, June 13, with a sudden increase in H of 40 gammas in five minutes, but with only very small initial D‐ and Z‐disturbances. Several long‐period and many short‐period small fluctuations showed. The principal activity ended at 09h, June 14. Ranges: D, 17′.3; H, 154 gammas.
Ionospheric Characteristics at Huancayo, Peru, for the Year 1940
Authors: Coile R. C. 
Published: February 2008

Ionospheric characteristics at the Huancayo Magnetic Observatory (12° 02′.7 south, 75° 20′.4 west) of the Department of Terrestrial Magnetism, Carnegie Institution of Washington, during the year 1940 have been published in quarterly reports in this JOURNAL [see 1 under 1 “References” at end of paper]. The present paper is a summary of reports on the data of 1940 and is the third of a series of annual papers summarizing ionospheric conditions at Huancayo [2]. Photographic records have been obtained with multifrequency equipment sweeping over a frequency‐range of 16.0 to 0.516 Mc/sec every 15 minutes continuously for 24 hours each day since December, 1937.This paper continues the method of presentation used in the annual summaries for 1938 and 1939 [2]. Ionospheric characteristics are presented as contour‐maps illustrating mean diurnal variation in critical frequency, minimum virtual height, and height of maximum electron‐density for each region. Full lines are contours of frequency or height and dotted lines represent the curve of mean data for the month indicated. These figures afford an effective means of distinguishing general characteristics and month‐to‐month trends by casual inspection.
The Sunspot‐Group Associated with the Magnetic Storm of September 18, 1941
Authors: Richardson R. S. 
Published: February 2008

If all intense magnetic storms could be as definitely related to a sunspot‐group as the one that began on September 18 about 04h 20m GMT, geophysicists would feel that one of their major problems was solved.The group associated with this storm was first seen on the east limb on September 10 and was fully in view. the following day. It then consisted of two spots of moderate size in latitude 12° north. These developed rapidly into a large active group with complex magnetic polarities. Groups of this type are generally considered most likely to cause storms. By September 17, the spot‐group had attained an area of 2000 millionths of the Sun's visible hemisphere which places it among the largest of the present cycle, a group of area 1000 being considered “large.” Since the date was near the autumnal equinox the latitude of the center of the disk was at its maximum value of 7° north. The spot‐group thus crossed the meridian about 5° north of the central point. When the storm began the spot‐group extended from 10° to 25° of longitude (or from about 0.8 to 1.9 days) west of the central meridian.
Sitka Magnetic Observatory, July to September, 1941
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 major magnetic storm began suddenly at 03h 52m GMT, July 4, with a sharp motion of all traces. Conditions remained comparatively calm with gradually increasing storminess until 06h, July 5. Until 16h, July 5, the trace was very disturbed and could be identified in only a few places. The K‐values during the storm were 9 for three three‐hour intervals. After 17h, July 5, there was a gradual return to normal.
Cheltenham Magnetic Observatory, July to September, 1941
Authors: Ludy Albert K. 
Published: February 2008

(Latitude 38° 44′.0 N., longitude 76° 50′.5 or 5h 07m.4 W. of Gr.)July 4–7—At 03h 43m GMT, July 4, a sudden commencement of a storm occurred. The abrupt change in H was an increase of 61γ; the abrupt D and Z changes were small. This was followed by several bays in D and irregular fluctuations in H and Z. After about five hours of activity all the elements became quiet until 17h, July 4, when mild activity was renewed. Then at 05h 40m, July 5, the storm broke into violent activity with four consecutive three‐hour periods with K‐number 9. There followed moderate activity until 12h, July 7, after which the storm gradually ended. Ranges: D, 252′; H, 1466 gammas; Z, greater than 1000 gammas.
Alibag Magnetic Observatory, April to June, 1941
Authors: Rangaswami M. R. 
Published: February 2008

(Latitude 18° 38′.3 N., longitude 72° 52′.3 or 4h 51m.5 E. of Gr.)April 24—A magnetic storm of moderate intensity commenced gradually at 07h 00m GMT, April 24. H was maximum at 07h 37m and began to fall afterwards and reached the minimum value at 16h 26m. The storm ended at about 22h. Ranges: D, 7′.7; H, 209 gammas; Z, 40 gammas.
Watheroo Magnetic Observatory, July to September, 1941
Authors: Parkinson W. C. 
Published: February 2008

(Latitude 30° 19′.1 S., longitude 115° 52′.6 or 7h 43m.5 E. of Gr.)July 4–7—This disturbance of unusual severity began at 03h 42m GMT, July 4, with sudden small movements followed by irregular, but relatively small, fluctuations in the traces. These conditions lasted until 04h 59m, July 5, when sudden impulses were recorded in all three elements and the traces immediately became violently disturbed,, remaining so until 16h. During this period H decreased to a value of 530 gammas below normal. The greatest sudden change in the interval was between 14h 07m and 14h 33m when H increased 285 gammas. Between 14h 23m and 14h 33m westerly declination decreased by 63′, which was practically the total range in declination during the whole disturbance. Z increased to such values between 08h and 15h that they were beyond the limits of registrations for the greater portion of the time. Although the violence of the disturbance had abated by 16h, July 5, and H had gradually regained its normal value, the traces continued to be moderately disturbed as follows: 20h to 22h on July 5; 13h to 16h on July 6; 00h to 05h on July 7. The disturbance ceased at 21h, July 7. Ranges: D, 65′2; H, 563 gammas; Z, greater than 215 gammas (probably more than 500 gammas). A brilliant display of the Aurora Australis was visible at the Observatory during the evening of July 5. At 10h 30m GMT, or 18h 30m 120° MT (E. of Gr.), an hour after sunset, a bright glow was seen on the southern horizon; it gradually became more pronounced and by 11h 50m had developed into an arch spreading from south‐southeast to south‐southwest and about 35° above the horizon at its highest part. At 12h 10m the arch was at its brightest and was tinged with red. at its eastern and western extremities. Brilliance then diminished slightly and by 12h 30m had almost disappeared, although the general glow still persisted. Between 14h and 14h 30m the glow, still visible, was varied by the appearance of luminous vertical shafts changing rapidly in range, intensity, and position. This display continued until after 14h 40m after which time only the glow was observed and this gradually faded. The whole display would have been even more imposing but for the presence of the Moon which was nearing the full.
Tucson Magnetic Observatory July to September, 1942
Authors: Nelson J. H. 
Published: February 2008

(Latitude 32° 14′.8 N., longitude 110° 50′1 or 7h 23m.3 W. of Gr.)July 10–12—A storm of moderate intensity began at 23h 35m GMT, July 10, with a sudden increase in H of about 25 gammas. The first fourteen hours of the storm consisted principally of irregular long‐period variations of D and H, with, as usual for this station, little disturbance of Z. The activity during the last half of the storm was less intense, and it ended about 12h, July 12. Ranges: H, 123 gammas; D, 16′; Z, 40 gammas.
Solar and magnetic data, October to December, 1942, Mount Wilson Observatory
Authors: Nicholson Seth B. , Mulders Elizabeth Sternberg 
Published: February 2008

A small magnetic disturbance occurred on October 2–3. Only very small sunspots were visible.Although an active sunspot‐group (Mount Wilson No. 7508) large enough to be seen without a telescope, crossed the central meridian on November 2.8 GMT, 14° from the center of the solar disk, no significant terrestrial‐magnetic activity was recorded while the group was visible (October 27–November 8).
Treatise on the Sphere and the Art of Navigation
Authors: Falero Francisco 
Published: February 2008

Part II, Chapter 8—On the northeasting1 of the needlesThe northeasting of the needles causes navigators many doubts, from which they may be freed by knowing precisely how much the needles northeast or northwest. In addition to this, other advantages will follow, such as knowing exactly in what direction they are sailing. Knowing this they will follow exactly their courses without error or wandering, and also it will help much to a knowledge of the longitude in which they are navigating.