bluuebunny/crossref_metadata_2025_split huggingface dataset:
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.
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 declination1—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.
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.
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.
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.
Note on the design of efficient magnets
Authors: Johnson E. A. 
Published: February 2008

The purpose of this note is to collect in a convenient form the design‐data for cylindrical magnets. Since the design which leads to maximum stability is not known, except that it appears that stability is greater when the coercive force is great and the energy product BH is great, the data presented here are for the purpose of determining the moment of a cylindrical magnet given the dimensions.In Figure 1 are given the demagnetization‐curves of Alnico, cobalt steel, and tungsten steel (left‐hand side) and the energy‐density (right‐hand side). In a cylindrical magnet, as in any magnet, the residual flux depends not only upon the externally applied demagnetizing force but also upon the demagnetizing force due to the interaction of the elementary magnets upon each other. This depends upon the magnetic circuit and in the case of a cylinder is composed of the cylinder and the surrounding medium, usually air. This self‐demagnetizing force is very small for an infinitely long cylinder, the case for which the curves are taken. The self‐demagnetizing force is proportional to the remanence in the specimen and the proportionality‐coefficient has been calculated for various ratios of length to diameter. The straight lines in Figure 1 passing through the origin represent these coefficients for the ratio of length to diameter given with each line. The intersection of these lines with the demagnetization‐curve of the selected material then gives the actual residual flux in a cylinder with the length‐to‐diameter ratio represented by the line.
American URSI Broadcasts of cosmic data, October to December, 1938, with American magnetic character‐figure CA, November, 1938 to January, 1939, and summary of CA for year 1938
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 Table 1 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 day, 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 (l0g+s), where the mean value of k for Mount Wilson was 0.53 during 1936; during 1937 this value varied from 0.47 to 0.66 with an average value of 0.53.
American URSI broadcasts of cosmic data, with American magnetic character‐figure CA, January to March, 1940
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 three columns for each month in Table 1 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 magnetic character of the year 1939 and the numerical magnetic character of days, 1939
Authors: van Dijk G. 
Published: February 2008

The annual review of the “Caractère magnétique de chaque jour” for 1939 has been drawn up in the same manner as for the preceding years. Sixty‐two observatories contributed to the quarterly tables; fifty‐three of them sent complete data.In the introduction a note has been inserted concerning the publication “Caractère magnétique numérique des jours” for 1939, volumes XXX–XXXIII have been published along with the tables of “Caractère magnétique de chaque jour.”
Final relative sunspot‐numbers for 1939 and monthly means of prominence‐areas for 1931–1939
Authors: Brunner W. 
Published: February 2008

Table 1 contains the final sunspot‐numbers for 1939, for the whole disk of the Sun, based on observations made at the Zürich Observatory, supplemented by series furnished by other cooperating observatories for days (indicated by asterisks) on which no observations were possible at Zürich.Table 2 gives the yearly means of the relative numbers, R, since the last minimum 1933 and the number of days without spots.
Tucson Magnetic Observatory April to June, 1940
Authors: White Roland F. 
Published: February 2008

April 2–4—At 16h GMT, April 2, minor activity started, with some increase in disturbance until 01h 30m, April 3, at which time there was a considerable increase, H having a range of 120 gammas and D a range of 15′ within one hour. This long‐period activity continued for seven hours and was followed by short‐period activity of small amplitudes to 23h, April 3. A slightly disturbed condition prevailed for about one day longer with no definite ending.April 25–26—A moderate storm began at 02h 05m GMT, April 25, with an increase in H of 45 gammas in two minutes, followed by a decrease of 190 gammas to a minimum at 05h 00m and then a return to normal. During the same period D increased 25′ and returned to normal at about the time of the minimum in H. The storm continued with moderate long‐period changes and a lowered H to an indefinite ending at about 12h, April 26.
Cosmic Radiation and Magnetic Storms [Reply to “Comments on A. R. Hogg's Paper ‘Cosmic Radiation and Magnetic Storms’”]
Authors: Hogg A. R. 
Published: February 2008

The comments by Mr. Forbush1 raise an interesting point in relation to the storm commencing at 3h.1, August 22, 1937.The world‐wide effect relative to Huancayo, has been shown by Mr. Forbush “reference 2 of comments” to be 1.11 for Cheltenham, 1.58 for Teoloyucan, and in the comments, 2.0 for Canberra. These figures have been used to effect a comparison between the Teoloyucan (1) and Canberra results (Fig. 1). There is quite a resemblance between these two curves, both showing a depression during the storm‐period. The depression for Teoloyucan, however, is not well marked, and in the average mentioned by Mr. Forbush is obliterated by the results from the other two stations (Huancayo and Cheltenham) combined with it.
Watheroo Magnetic Observatory, January to March,, 1941
Authors: Parkinson W. C. 
Published: February 2008

January 3–4—A small magnetic disturbance began with a sudden commencement at 15h 43m GMT, January 3. A quiet period of eleven hours ensued, after which the traces were mildly disturbed until normal conditions resumed at 12h, January 4. Ranges : D, 14′.1; H, 85 gammas; Z, 59 gammas.January 24—During somewhat disturbed conditions which prevailed on January 24, there was one noteworthy feature. Between 12h and 14h there was a wave of large amplitude in all three elements. In H the movement began at 12h 20m with a bay which reached its minimum at 12h 42m and then rose sharply to a peak at 12h 59m, then gradually falling to approximately normal value by 13h 50m. Ranges: D, 23prime;.9; H, 107 gammas; Z, 135 gammas.
Tucson Magnetic Observatory, July to September, 1941
Authors: Nelson J. H. 
Published: February 2008

(Latitude 32° 14′.8 N., longitude 110° 50′.1 or 7h 23m.3 W. of Gr.)July 4–8—The storm began with a sudden increase in H of 41 gammas at 03h 42m GMT, July 4, with evidence of mild activity until 00h, July 5. During the following five hours there was a gradual increase of activity. At 05h 00m, July 5, another sudden increase in H marked the beginning of a severe magnetic storm. The extreme activity of the storm ended at 15h, July 5. Moderate disturbance with considerable short‐period and some long‐period variations continued until about 09h July 8. Approximate ranges: H, 393 gammas; Z, 156 gammas; D, 36′.
Some Early Contributions to the History of Geomagnetism—II AND III
Authors: Harradon H. D. 
Published: February 2008

(II) Francisco Falero—During the great age of discovery which followed the voyages of Columbus, Spain and Portugal took an important part in maritime enterprises and the exploration of lands beyond the sea. These ventures were responsible for the improvement of instruments and methods of navigation and the production of charts and maps. At that time it was widely believed that the determination of longitude at sea could be obtained from magnetic data, particularly from those of the declination, a belief which persisted throughout the seventeenth century and encouraged the making of many magnetic observations which, although useless as far as longitude‐determinations were concerned, at least furnished data of great value in advancing knowledge of geomagnetism.The first person who announced practical methods of determining the magnetic declination in printed form was Francisco Falero or Faleiro, a Portuguese in the service of the Spanish Navy, to whom we are indebted for the first real manual of navigation. This work entitled “Tratado del esphera y del arte del marear; con el regimie˜to de la altura; cõ algũas reglas nueuame˜te escritas muy necessarias,” is extremely rare—so rare in fact that its existence has sometimes been doubted. The National Library in Madrid, however, possessed a copy and Hellmann was enabled to reproduce its title‐page which we in turn present herewith in Plate 2. (A free translation of the title is as follows: 'Treatise on the sphere and the art of navigation with manual of altitudes with some very necessary written rules. With imperial privilege. A. D. 1535.”) The work was printed in gothic type and consists of 52 unnumbered folio pages. In the eighth chapter of the second part under the title "Del nordestear de las agujas,” a translation of which we present (page 80), magnetic declination is discussed in detail for the first time in print and three methods are given for its determination, namely (1) by the azimuth‐determination of the magnetic needle at true noon when the shadow of the pin falls to the north, (2) by observation of the shadow‐azimuths at corresponding altitudes of the Sun before and after noon, (3) by observation of the azimuth at sunrise and sunset.1 These methods are perhaps intended for an instrument (brújula de variación) devised by Filipe Guillen although no mention is made of it.
On the Observational Evidence for Changes in Ionization of the Upper Atmosphere Attributable to the Moon
Authors: Stetson Harlan T. 
Published: February 2008

Evidence for the effect of the Moon upon radio‐wave propagation has been previously presented by the author on several occasions [see 1, 2 of “References” at end of paper]. The evidence presented was based upon studies of field‐strength measurements showing variations in field‐intensities at broadcast‐frequencies over fixed paths with the hour‐angle of the Moon. The variations noted indicated a single rather than a double maximum for the lunar day. It was suggested that the considerable variations observed were greater than would be easily satisfied by an explanation based on the lunar gravitational tide in the Earth's atmosphere alone. Analyses of long years of magnetic observations have clearly shown a lunar component in changes in declination and intensity of the Earth's magnetic field, the major part of which may be ascribed to changes in ionic distribution in the upper atmosphere.It is interesting to note that at the Rome meeting of the International Scientific Radio Union, Appleton [4] reported a lunar semi‐diurnal variation of the level of the E‐layer of approximately one km, the maximum occurring about three‐quarters of an hour before the lunar transit. The results were based upon a single year's investigation in the determination of equivalent heights by reflection from the E‐region of the ionosphere. Appleton regards the results as showing a pressure oscillation of a relative amplitude of 0.068 at a level of 100 km and calls attention to the fact that the measurement of the lunar barometric oscillations at ground‐level show a corresponding relative amplitude of only 0.0000115. If this interpretation is correct, the tide at 110 km, he points out, is 5900 times that of ground‐level. The phase of the upper atmospheric tide was found by Appleton to be the same as that at ground‐level at Greenwich, a result not consistent with deductions made from lunar magnetic variations, assuming such variations to arise from currents flowing in the E‐region.
Discussion of “Atmospheric‐Electric Observatories at Huancayo, Peru, during the Solar Eclipse, January 25, 1944”
Authors: Gish O. H. 
Published: February 2008

The correlation, reported by Jones and Giesecke, between certain variations in atmospheric‐electric elements, and the progress of the solar eclipse, appears to be more significant than any seen by the writer, in similar observations made elsewhere during solar eclipses [see 1, 2, 3, 4 of “References” at end of paper] except the observations [1] made at Lakin, Kansas, during the eclipse of June 8, 1918, which show effects that appear to have about the same significance. A comparison of the eclipse‐effects indicated at these two places derives some of its interest from the fact that the “normal” diurnal variation of potential‐gradient and that of air‐conductivity at Lakin seems to be of about the same character as that found for the respective elements at Huancayo on most fair‐weather days, namely, values of air‐conductivity are conspicuously larger at night than in daylight, while the values of potential gradient are larger in daylight and small at night and at both places the diurnal variation of air‐earth current is apparently free from this local time‐component. Although the data bearing on diurnal variation, obtained at Lakin, Kansas, consist of manual observations for one 24‐hour period only, confidence in the indicated character of diurnal variation is strengthened by the fact that the four independently measured elements, namely, potential‐gradient, positive conductivity, negative conductivity, and positive ion‐concentration, all show the pronounced and consistent difference between daylight and night.Meteorological conditions reported for the period of observations at Lakin are favorable for the development there of a stable stratum of air adjacent to the Earth at night. The latter is an important feature in the mechanism proposed by the writer [5] to explain the remarkable local aspect of diurnal variation in the several elements at Huancayo and it accordingly seems likely that the diurnal variation observed at Lakin is also attributable to such a mechanism. One may therefore expect an eclipse of the Sun to affect the atmospheric‐electric elements in a similar manner at the two places, namely, tend to establish, during the eclipse, values which are characteristic of night.
On the Determination of Magnetic Vertical Intensity, Z, by Means of Surface Integrals
Authors: Taylor James H. 
Published: February 2008

Introduction— The. main result of the present paper is a separation of Z, the normal component of a magnetic field, into parts Ze and Zi due to external and internal sources, respectively. The resolution is given in terms of surface integrals whose integrands involve the observed surface values X and Z of the field. The paper may well be regarded as a sequel to an article by Vestine [1 of “References” at end of paper].The author is greatly indebted to Dr. Vestine, who proposed the investigation and gave invaluable suggestions regarding it. The author is also grateful to Dr. Davids, who provided certain computational details relating to the eccentric dipole field, and who made available results that he had obtained which seemed to have a bearing on the problems under consideration.
Analysis and Interpretation of Geomagnetic Anomalies
Authors: Vestine E. H. , Davids N. 
Published: February 2008

The analysis and interpretation of geomagnetic anomalies is discussed. Techniques are described for estimating depth and strength of magnetized ore‐bodies, using tables and graphs of the fields of simple models. Relations among surface‐components of field of anomalies are derived, using fitting or representation of anomalies by Fourier series, Fourier‐Bessel series, and power series. A method based on the analysis of surface magnetic fields by integrals is also described.Methods are given for estimating probable minimum and maximum depths to magnetic sources beneath the Earth's surface, using measurements of field at the surface. The locations of sources cannot be uniquely inferred from magnetic data alone. The use of gradients of field in locating sources of anomaly is indicated.