bluuebunny/crossref_metadata_2025_split huggingface dataset:
On the contribution to the ionization at sea‐level produced by the neutrons in the cosmic radiation
Authors: Korff S. A. 
Published: February 2008

Since neutrons constitute a numerically important component of the cosmic radiation [see 1 of “References” at end of paper], the question arises as to the amount of ionization in the atmosphere at sea‐level which they produce. This ionization will be produced in two ways: (a) By recoil‐nuclei produced by the neutrons in collisions; and (b) by the ionizing radiation ejected from nuclei as a result of neutron‐induced disintegrations. We may set limits to each of these contributions.It is believed that most of the neutrons in the atmosphere at sea level are evaporated out of nuclei by the high‐energy cosmic radiation, and have initial energies of 10 to 30 Mev. It has been pointed out by Bethe, Korff, and Placzek [2] that these neutrons will first be inelastically scattered by nitrogen nuclei. In this process, the neutron enters the nitrogen nucleus, causes the ejection of one or more nuclear particles, and usually emerges with about four Mev energy. The bulk of the energy of the neutron is used in breaking up the binding of the nucleus, and hence is not transformed into ionization. The ionizing particles which are emitted will in general have energies which are small compared to the initial energy of the neutron, and it may be estimated [2] that of the order of five Mev per neutron will appear as ionization.
The ionosphere at Huancayo, Peru, October to December, 1939
Authors: Wells H. W. , Coile R. C. 
Published: February 2008

This report on ionospheric conditions is in continuation of those published in preceding issues of this Journal submitting results of continuous multifrequency ionospheric recordings at the Huancayo Magnetic Observatory, Department of Terrestrial Magnetism, Carnegie Institution of Washington. The current data for October, November, and December, 1939, are obtained from recording for each hour of the day and for every day of the month except for short intervals necessary for maintenance of the equipment. This multifrequency apparatus sweeps through a frequency‐range from 16.0 to 0.516 mc/sec every 15 minutes.Table 1 contains mean hourly values of virtual height, critical frequency, and lowest frequency received for the fourth quarter of 1939. Figure 1 presents the data of Table 1 in graphical form. The following general discussion of characteristics is pertinent.
Ionospheric characteristics at Huancayo, Peru, for the year 1939
Authors: Wells H. W. , 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, for the year 1939 have been published in quarterly reports in this Journal [see 1 under “References” at end of paper]. The present paper is a recapitulation of the reports for the year 1939, and is a sequel to the analysis for the period December, 1937, through December, 1938 [2]. The 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—except for occasional short intervals necessary for maintenance—since December, 1937.This paper continues the method of presentation used in the annual report for 1938 [2]. The figures are relief maps illustrating mean diurnal variation in critical frequency or virtual height 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 the general characteristics and month‐to‐month trends by casual inspection.
The Ionosphere at Watheroo, Australia, October, 1940, to March, 1941
Authors: Parkinson W. C. 
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 ionosphere as obtained by means of automatic multifrequency ionospheric recording apparatus located near Watheroo, Western Australia, in latitude 30° 19′.1 south, longitude 115° 52′.6 east of Greenwich, which operates over the frequency‐range 0.516 to 16.0 Mc/sec.Table 1 gives the monthly mean hourly values of the height of maximum electron‐density (hmax), unconnected 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 higher than 0.516 Mc/sec.
Alibag Magnetic Observatory, October to December, 1940
Authors: Rangaswami M. R. 
Published: February 2008

October 26—A moderate disturbance began suddenly at 07h 23m GMT, October 26. H attained its maximum at 08h 02m and then began to fall with fluctuations to reach the minimum at 17h 20m. The disturbance ended at approximately 23h.5. Ranges: D, 4′.9; H, 185 gammas; Z, 45 gammas.November 12–13—A moderate disturbance began with a sudden commencemt at 07h 06m GMT, November 12. H attained its maximum at 07h 38m, and then fell until llh.5, November 12, after which the oscillations became more pronounced. The minimum in H occurred at 05h 01m, November 13. The disturbance practically ended at 08h, November 13, although minor fluctuations continued for a period of short duration. Ranges: D, 3′.5; H, 145 gammas; Z, 117 gammas.
Magnetic Observatory, Capetown, October to December, 1940
Authors: Ogg A. 
Published: February 2008

September 30–October 1—Disturbance began at 19h GMT, September 30. Marked bays developed on all traces at 01h, October 1, but otherwise the fluctuations were not large. At 11h 54m the disturbances became more marked and continued until 22h. H decreased 121 gammas in the period from 01h 52m to 18h 00m, while the decrease was 86 gammas from 15h 01m to 18h 00m.October 3—Bays appeared on all traces at 18h GMT, October 3. The magnitude of the H‐bay was +38 gammas in forty minutes and then −20 gammas in sixty minutes.
Cape Town Magnetic Data
Authors: Ogg A. 
Published: February 2008

The reduction and analysis of all data collected at the Magnetic Observatory, Cape Town, during the years 1933–40 have been completed with the exception of certain details with regard to the last six months of 1940, such as the international quiet and disturbed days which have not yet been announced.The publication of the observations during the first four years was delayed by the printer and it is impossible, at the present time, owing to the existing war conditions, to proceed with their publication.
The Corpuscular Geomagnetic Index and Related Solar Changes
Authors: Clayton H. Helm 
Published: February 2008

In that part of geomagnetic changes associated with solar changes the experts of the Department of Terrestrial Magnetism of the Carnegie Institution of Washington have distinguished two types of change, one associated with short‐wave solar radiation coming from flares visible on the surface of the Sun and the other attributed to electrified particles coming from the Sun. The first kind of disturbance travels with the velocity of light and reaches the Earth in a few minutes after the solar flares are seen. They affect only the sunlit side of the Earth and are principally noticeable in the equatorial regions of the Earth.The second class of disturbance, associated with electrified particles, travels more slowly and effects the sunlit and dark sides of the Earth equally. These disturbances are most felt in the polar regions and when strong are associated with magnetic storms, auroras, and radio interruptions. The corpuscular radiation has been standardized to eliminate local effects and is now published by Science Service for every three hours as deduced from seven observatories scattered around the Earth and are called KA‐values. In addition complete values of K for the year 1938 and 1939 are published in Terrestrial Magnetism and Atmospheric Electricity for September, 1940, as compiled by Bartels, Heck, and Johnston.
Sitka Magnetic Observatory, October to December, 1941
Authors: Gebhardt Robert E. 
Published: February 2008

(Latitude 57° 03′.0 N., longitude 135° 20′1 or 9h 01m.3 W. of Gr.)October 11–12—A small disturbance began gradually at 06h GMT, October 11. The intensity increased gradually to maximum storminess at 10h. After 14h conditions began to return to normal. The trace remained moderately disturbed until 12h, October 12. The maximum K‐index registered during this period was 8.
Watheroo Magnetic Observatory, October to November, 1941
Authors: Parkinson W. C. 
Published: February 2008

(Latitude 30° 19′.1 S., longitude 115° 52′.6 or 7h 43m.5 E. of Gr.)October 31–November 1—This moderate disturbance began with a small sudden commencement at 03h 40m GMT, October 31. The movements thereafter were of no great amplitude until 17h when they gradually became more pronounced. The value of horizontal intensity decreased markedly after 22h. The fluctuations remained moderately active but nothing of importance was recorded until 10h, November 1, when a double bay of about one hour's duration occurred in all three elements. The double bay was repeated on a smaller scale between 13h 40m and 14h 50m on the same day. The traces rapidly became normal after 16h, November 1. Ranges: D, 19′.0; H, 173 gammas; Z, 149 gammas.
Notes on Isomagnetic Charts: VII—Mathematical Notes on Isoporic Charts and Their Singular Points
Authors: Chapman Sydney 
Published: February 2008

Summary—The nature of the isoporic lines is examined for the magnetic potential V and for the magnetic elements D, H, I, Z, and F. In general the singular points on an isomagnetic chart are not singular points on the corresponding isoporic chart, and vice versa. In particular, the singular points for V, which are dip‐poles, are usually not singular points for its rate of change
. But the dip‐poles are singular points not only for D, H, and I (though not in general for Z and F) but also for
,
, and
(though not in general for
and
).If the dip‐pole is moving, it is a double focus for
(which there takes all values from −∞ to +∞), and a non‐uniform ray‐pole for
and
the relation of the isopors to the velocity of the dip‐pole is indicated. If the dip‐pole is stationary, it is a non‐uniform ray‐pole for
and a conical focus or node for
(which there is zero) and for
.The isopors for V, D, H, I, Z, and F for the field of a varying centered dipole are determined and illustrated. It is shown that in the region around an associated pair of local dip‐poles the isopors must be very complicated, those for D, for example, having at least eight singular points in the region. The isopors near the principal geomagnetic dip‐poles are discussed, and it is shown that in these regions certain isoporic charts appear to be inconsistent with theory.The isoporic charts for 1922 for D and H given, by the Admiralty and by H. W. Fisk are compared and discussed. For 126 points uniformly spaced at 20° intervals the average numerical difference between the indications of the two charts is 56 per cent for
, and 69 per cent for H, of the average numerical value of D and H, respectively, at these points.
Height of Maximum Electron‐Density in the Ionosphere
Authors: Booker H. G. 
Published: February 2008

It has been pointed out1 that, if one is willing to fit a parabolic maximum of electron‐density to an ionospheric region, an index of actual height of maximum electron‐density is given by the virtual height at five‐sixths of the penetration‐frequency. Monthly averages of the diurnal variation of this index, uncorrected for presence of lower regions, are now published for Watheroo (Western Australia)2 and Huancayo (Peru).3 The procedure has been criticized by Rawer,4 who states that a different index is used in Germany.Accurate calculation of the actual height of maximum electrondensity from recorded multifrequency observations is a difficult matter and any procedure sufficiently simple for application to a large number of records is inevitably open to the charge of inaccuracy. Rawer correctly points out that, had we chosen to fit some non‐parabolic distribution of electron‐density, our index of the height of maximum electron‐density would have been affected. However, we are not irretrievably attached to the parabolic distribution and if it can be shown that some other distribution is more reliable and equally convenient we would be quite willing to change.
Tucson Magnetic Observatory, January to March, 1942
Authors: Nelson J. H. 
Published: February 2008

(Latitude 32° 14′.8 N., longitude 110° 50′.1 or 7h 23m.3 W. of Gr.)February 23–25—A moderate storm began at about 14h GMT, February 23, and ended at about 02h, February 25, with several long‐period and many short‐period oscillations. The main part of the disturbance stopped at about 10h, February 24, but considerable short‐period activity continued until the end of the storm. Ranges: D, 22′; H, 49 gammas; Z, 11 gammas.
Apia Observatory, January to March, 1942
Authors: Sapsford H. Bruce 
Published: February 2008

(Latitude 13° 48′.4 S., longitude 171° 46′.5 or 11h 27m.1 W. of Gr.)March 1–2—A sudden commencement at 07h 27m GMT, March 1, marked the beginning of a magnetic storm of short duration. The increase in the magnetic field was in two steps: H rose 68 gammas in one minute and then fell momentarily before rising, two minutes after the commencement, to a turning point 87 gammas above the undisturbed level. The Z‐trace showed the motion more clearly, the three turning points within two minutes of the start being quite distinct; they had values of 32, 22, and 33 gammas, respectively, above the pre‐storm level. The intensity of H and Z remained above normal for about two hours and then a rapid fall took place until about 10h, the minimum in Z occurring at 09h 51m. There were minor oscillations in H for further period until the minimum at 12h 54m. Very rapid small oscillations were superimposed on the larger movements from the start and continued until about 02h, March 2. D showed large fluctuations with a westerly trend in the early part of the storm. Ranges: D, 8′.2; H, 260 gammas; Z, 43 gammas.
On Alfven's theory of magnetic storms and of the aurora
Authors: Cowling T. G. 
Published: February 2008

H. Alfven, in recent papers [Stockholm, Vet‐Ak. Handl., 18, No. 3 (1939) and No. 9 (1940)], attributes magnetic storms and auroras to a stream of ions and electrons emitted from the Sun, the electrons with energies about 108 volts and the ions with smaller energies. The theory differs from Chapman and Ferraro's theory of magnetic storms by taking into account the magnetic field of the Sun and supposing that the motion of any individual particle is hardly affected by the magnetic field due to the motion of other particles.The outward motion of the stream from Sun to Earth is explained as due, not to the original outward velocities of the particles, but to electromagnetic effects. Alfven divides the motion of a particle in the Sun's magnetic field into four parts (see Note 1 on page 212):
Cheltenham Magnetic Observatory April to June, 1942
Authors: Hershberger John 
Published: February 2008

April 2‐5—A moderate disturbance began rather indefinitely at about 11h GMT, April 2, and seemed to have ended twenty‐four hours later, the highest K‐index for this period being 5. But an abrupt renewal of activity occurred at 19h 18m, April 3, with a sudden increase in H. The disturbance ended at about 06h, April 5. There were several large bays, giving K‐indices of 6 for two successive three‐hour periods.April 10‐11—A moderate disturbance began sharply at 23h 02m GMT, April 10, and ended at 16h, April 11. The first four three‐hour periods of April 11 had K‐indices of 5.
Some early contributions to the history of geomagnetism: I
Authors: Harradon H. D. 
Published: February 2008

The writing of a detailed and comprehensive history of geomagnetism would present many difficulties, because the beginnings are almost hopelessly obscured by myths and legends and many important points are still subjects of uncertainty and controversy. Some light has been thrown on mooted questions by scholars in recent times, but much still remains to be clarified regarding the discovery of the directive power of the Earth's field and its practical application.1There are, however, a number of documents which may be regarded as milestones in the development of geomagnetic knowledge and whose importance from a historical viewpoint is undisputed. Unfortunately, all these early writings have become extremely rare and the few extant copies are preserved in widely distributed libraries. In order to make them more generally available, G. Hellmann was led to reproduce, partly in facsimile, some of the more important contributions in his “Rara Magnetica” [Neudrucke von Schriften und Karten über Metorologie und Erdmagnetismus, No. 10, Berlin, Asher und Co. (1898)].
American Magnetic Character‐Figure, CA, Three‐Hour‐Range Indices, K, and Mean K‐Indices, KA, for January to March, 1943
Authors: Johnston H. F. 
Published: February 2008

Summaries of American URSI broadcasts have appeared regularly in this JOURNAL since the issue for December, 1930.As set forth in this JOURNAL for June, 1937, “The Department of Terrestrial Magnetism and the United States Coast and Geodetic Survey with the cooperation of the United States Army and the United States Navy communication‐services and several amateur radio stations have undertaken to supply the American character‐figure based upon the reports of the seven American‐operated observatories—those of the Department of Terrestrial Magnetism at Huancayo in Peru and at Watheroo in Western Australia, and those of the United States Coast and Geodetic Survey at Cheltenham (Maryland), Honolulu (Hawaii), San Juan (Puerto Rico), Sitka (Alaska), and Tucson (Arizona).” This character‐figure is being designated CA, and its values for the first twelve, the second twelve, and all twenty‐four hours of each Greenwich day for January to March, 1943, are given in Table 1.
Summary of the Year's Work, to June, 1944, Department of Terrestrial Magnetism, Carnegie Institution of Washington
Authors: Fleming J. A. 
Published: February 2008

Geomagnetic progress during the year July 1, 1943, to June 30, 1944, even though practically all the men of the staff were engaged in war problems, was good. This is attributable to the fact that many of these problems required research utilizing the wealth of observational, theoretical, and instrumental material already in hand through the work and compilations of the Department during 40 years.Of the ten nonprofit contracts undertaken by the Carnegie Institution of Washington in this Department and still active June 30, 1943, one with the Office of Scientific Research and Development, three with the National Defense Research Committee, and one with the United States Navy were successfully concluded. Continuing or extended nonprofit contracts include two with the National Defense Research Committee, two with the United States Navy, and one with the United States Army. Two new nonprofit contracts were made with the United States Navy—one for the Naval Research Medical Center and one for the Naval Hospital—and two more were arranged to begin after July 1, 1944, one of these with the United States Navy for its Naval Hospital and one with the United States Public Health Service for its National Institute of Health.
American Magnetic Character‐Figure, CA, Three‐Hour‐Range Indices, K, and Mean K‐Indices, KA, for Jult to September, 1944, and Five International Quiet and Disturbed Days for April to June, 1944
Authors: Johnston H. F. 
Published: February 2008

Summaries of American URSI broadcasts have appeared regularly in this JOURNAL since the issue for December, 1930.As set forth in this JOURNAL for June, 1937, “The Department of Terrestrial Magnetism and the United States Coast and Geodetic Survey with the cooperation of the United States Army and the United States Navy communication‐services and several amateur radio stations have undertaken to supply the American character‐figure based upon the reports of the seven American‐operated observatories—those of the Department of Terrestrial Magnetism at Huancayo in Peru and at Watheroo in Western Australia, and those of the United States Coast and Geodetic Survey at Cheltenham (Maryland), Honolulu (Hawaii), San Juan (Puerto Rico), Sitka (Alaska), and Tucson (Arizona).” This character‐figure is being designated CA, and its values for the first twelve, the second twelve, and all twenty‐four hours of each Greenwich day for July to September, 1944, are given in Table 1.
The Gulf Absolute Magnetometer
Authors: Vacquier Victor 
Published: February 2008

In response to the need for a more accurate method of measuring the vertical magnetic intensity in the field, voiced to me in 1938 by Captain N. H. Heck, of the United States Coast and Geodetic Survey, the Gulf Research and Development Company built an absolute magnetometer of new design for the determination of declination (D), vertical intensity (Z), and horizontal intensity (H). The declination is measured in the customary manner by means of a fiber‐suspended magnet. The intensity‐measurements are made by comparing the field of a Helmholtz coil with the component of the Earth's field that is to be measured. H is obtained by the sine‐galvanometer method. The zero‐field detecting device for Z is a special vertical field‐balance in which the polarity of the magnet can be reversed by discharging a condenser through magnetizing coils fastened to the case. The effect of residual mechanical unbalance is thus made to disappear from the average of two sets of observations taken with the magnet oppositely polarized, The Helmholtz coil‐constant for the Z‐magnet is determined by suspending the Z‐magnet in the sine‐galvanometer housing, and comparing the value of H so obtained with an observatory base‐line.From preliminary tests at Cheltenham in April, 1940, the declination‐error was 1.′6. The precision of the intensity‐measurements is limited entirely by the stability of electrical standards in the field. This is estimated to be between 0.01 and 0.02 per cent. Six standard cells, two standard resistors, and one Rubicon potentiometer comprise the electrical measuring‐equipment. The determination of Z on the basis of the Cheltenham base‐line for H and the electrical equipment of the CIW sine‐galvanometer No. 1 was 17γ greater than the Cheltenham base‐line for Z. This discrepancy can be accounted for either by pier‐differences or by a magnetic impurity in the construction of the Z‐balance. The tests were interrupted by the war. Since little remains to be done to the instrument, it is hoped that it will be made ready for the postwar observational program at an early date.
American Magnetic Character‐Figure, CA, Three‐Hour‐Range Indices, K, and Mean K‐Indices, KA, for January to March, 1945
Authors: Johnston H. F. 
Published: February 2008

Summaries of American URSI broadcasts have appeared regularly in this JOURNAL since the issue for December, 1930.As set forth in this JOURNAL for June, 1937, “The Department of Terrestrial Magnetism and the United States Coast and Geodetic Survey with the cooperation of the United States Army and the United States Navy communication‐services and several amateur radio stations have undertaken to supply the American character‐figure based upon the reports of the seven American‐operated observatories—those of the Department of Terrestrial Magnetism at Huancayo in Peru and at Watheroo in Western Australia, and those of the United States Coast and Geodetic Survey at Cheltenham (Maryland), Honolulu (Hawaii), San Juan (Puerto Rico), Sitka (Alaska), and Tucson (Arizona).” This character‐figure is being designated CA, and its values for the first twelve, the second twelve, and all twenty‐four hours of each Greenwich day for January to March 1945, are given in Table 1.