bluuebunny/crossref_metadata_2025 huggingface dataset:
The magnetic observatories of the United States Coast and Geodetic Survey in operation on July 1, 1902
Authors: Bauer L. A. , Fleming J. A.
Published: February 2008

I. SELECTION OF SITES OF THE MAGNETIC OBSERVATORIES.

[Abstract].1

The United States Coast and Geodetic Survey has in operation, in conformity with the plan of the magnetic survey of the United States and countries under its jurisdiction, outlined in Appendix 10, Report of the Superintendent of the Coast and Geodetic Survey for 1899,2 four magnetic observatories at which the manifold variations of the Earth's magnetism are being continuously recorded by photographic means. These continuous records, besides serving other useful purposes, are utilized in referring the values of the magnetic elements, obtained at various stations and at various times by the field parties engaged in the magnetic survey, to a common time.
Solar magnetism
Authors: Humphreys W. J.
Published: February 2008

The recent study of Sun‐spots by Hale1 and his coworkers at the Carnegie Solar Observatory on Mount Wilson has led to important discoveries, of which probably the most fundamental are:

(a) That the spots are cooler2 than the surrounding regions;

(b) That they are centers of violent cyclones;

(c) That they are accompanied by magnetic fields of great intensity.

Many numerical details and other discoveries are to be expected from this Observatory at any time, but, accepting the above conditions as definitely proved to exist, the author begs to submit the following discussion of them.
Concerning position of South Magnetic Pole
Authors: van Bemmelen W.
Published: February 2008

The position of the South Magnetic Pole referred to in this Journal, vol. XIII, p. 186, is as given by Commander Chetwynd in his discussion of the absolute observations made by the Expedition. “National Antarctic Expedition, Physical Observations,” p. 133, Charts I and II. The position finally obtained by Commander Chetwynd for, say, 1903, “Physical Observations,” p. 156, is 72°51′S., 156°25′E. [The declination observations gave a position, 72°50′ S., 156°20′ E., and the inclinations, 72°52′ S., 156°30′ E.]
On time scalings of magnetograms
Authors: Faris R. L.
Published: February 2008

From some of the recent discussion2 that has appeared in reference to the accuracy of the time scalings of magnetograms (photomagnetic records) in connection with the study of the non‐simultaneity of abruptly beginning magnetic storms it would seem helpful to a clearer understanding of the subject to state specifically the method of time scalings that has obtained in reducing the results of the Coast and Geodetic Survey magnetic observatories.

The five magnetic observatories of the Coast and Geodetic Survey are all equipped with a complete set of Eschenhagen type of variometers3 (Cheltenham having also an Adie magnetograph) and the photographic recording apparatus is so arranged that a time interval of one hour on the magnetograms is approximately twenty millimeters in length, thus making one millimeter correspond to a three minute time interval. The beginning of each hour is recorded on the base lines of the magnetogram by the light from the fixed mirrors of the variometers being interrupted, for a short interval of time, by small automatic shutters in the recording apparatus. The magnetic traces as well as the base‐lines are mechanically interrupted (by the observer) at least once each day, usually about 8 o'clock every morning. The time of this interruption, or break in the curves and base‐lines, is recorded. The error of the driving clock of the recording apparatus is then known from these daily comparisons with the standard observatory chronometer, the error of the latter on local mean time is known certainly to one‐tenth of a minute of time from observations made for the purpose about once a week or oftener if found necessary. There are five points on each magnetogram of about 24 hours' length, where time comparisons are made with the standard observatory chronometer, all five of which are recorded on the base lines, and three of which are recorded on the magnetic curves themselves, viz: at the beginning of the twenty‐four hour record (when the new photo‐sheet is put on), usually about 4:10 p.m., then another time comparison at the 5:00 p.m. hour break; the third reading is made about 8:00 a.m. the following morning (when the interruption of the magnetic trace is made as above mentioned) ; the fourth comparison of the time is made at the 4:00 p.m. time break, and finally a reading of the time is made at the close of the twenty‐four hour record when the photographic sheet is removed from the drum of the recording apparatus. As soon as the magnetogram is taken from the recording apparatus it is marked with distance marks (small holes are pricked through from the back of the trace at a known distance apart, by two small metal points fixed in a small wooden beam, like a beam compass), so that on the finished record, after it has been developed and fixed, the correction for shrinkage of the traces can be made if necessary, in scaling the ordinates when making the numerical tabulations.
The atmospheric potential gradient, and a theory as to the cause of its connection with other phenomena in atmospheric electricity, together with certain conclusions as to the expression for the electric force between two parallel charged plates
Authors: Swann W. F. G.
Published: February 2008

The primary purpose of the following paper is to show that the theory of conduction of electricity in gases, combined with the assumption of an atmospheric potential gradient of such a sign that the potential increases with the height, leads us to expect:1

(1) That the ratio of the number of positive ions per c. c. at the Earth's surface, to the number of negative ions shall be greater than unity.
On the origin and maintenance of the Earth's charge: 1.
Authors: Swann W. F. G.
Published: February 2008

Introduction. The above subject will be discussed in two parts. Part I, which comprises the present communication, is devoted to a discussion of certain matters of a general nature which must be considered in connection with the formulation of any theory of the cause and maintenance of atmospheric‐electric phenomena. A consideration of the various possible types of hypotheses is made, and a short discussion of former theories is given, more particularly in the light of the above considerations.
On the ionization of the upper atmosphere
Authors: Swann W. F. G.
Published: February 2008

The subject of the ionization of the upper atmosphere is one of extreme importance to students both of Terrestrial Magnetism and of Atmospheric Electricity, and from various points of view there are indications that this region of the atmosphere is to be treated as one of relatively high electrical conductivity. One of the first theories which took this hypothesis as one of its bases was that developed by Schuster1 to account for the diurnal variation of the Earth's magnetism.

At the time when Schuster's paper was written the most natural source in which to seek an explanation of the high conductivity was the ultra‐violet light from the Sun. The great increase in our knowledge of photo‐electric ionization within the last few years renders it now possible to make a closer scrutiny of the consequences to be anticipated from the ultra‐violet ionization alone. Any conclusions as to the insufficiency of this source for accounting for such a conductivity as that cited by Schuster must not, of course, be considered in any way as a criticism regarding the broad principles underlying Schuster's work, since the ultra‐violet light is by no means the only source of ionization of the atmosphere. Indeed, Schuster himself questioned the sufficiency of this source, and he took pains to point out that other sources were available. Thus, the rate of production of ions in a closed vessel increases at altitudes of 10 kilometers to many times its value at the Earth's surface, and this fact suggests a powerful ionization agent in the upper atmosphere other than the ultra‐violet light. In spite of the existence of various agencies which may be invoked to account for the ionization in question, it is not without interest to discuss in terms of modern views as to photo‐electric ionization the possibilities inherent in the ultra‐violet light alone.
Remarks on non‐cyclic changes and calm days
Authors: Bauer Louis A.
Published: February 2008

1. The foregoing article (pp. 69‐77) by Dr. Chree has particular reference to an item of the Madrid meeting of the International Section of Terrestrial Magnetism and Electricity pertaining to the application of non‐cyclic corrections in terrestial magnetism and atmospheric electricity which, owing to limited time, could not fully be discussed and regarding which no agreement was reached. Dr. Chree has concerned himself with the application of non‐cyclic corrections for a period of about two decades, but he has had few followers in the method adopted by him. It should be recalled that he has chiefly dealt with the discussion of the so‐called quiet days (limited to 5 per month in the case of terrestrial magnetism, and to 10, in atmospheric electricity).

2. The mean values of results from the selected quiet days are frequently termed “normal” values, though, as a matter of fact investigations have repeatedly shown that the quiet clays are as subject to a special kind of disturbance, though to be sure to less extent, as are the greatly disturbed days. This fact is admirably shown in Father de Moidrey's timely article (pp. 79‐82). Instead of the quiet‐day values representing normal conditions they should be looked upon as representing subnormal conditions; it is as bad at times for a patient to have a sub‐normal temperature as a high temperature. On the average, about 65‐70 per cent of the five magnetically‐quiet days per month selected at the De Bilt Observatory, on the basis of characterization lists received from the operating observatories, are the days of minimum range in horizontal intensity. Sometimes it happens that a magnetic‐activity measure based on the assumption that the quiet days represent normal conditions turns out negative, and, hence, does not admit of physical interpretation. It has even occurred that the monthly mean diurnal range for the selected 5 quiet days was higher than the monthly mean diurnal range obtained from the 10 least disturbed days per month. We, accordingly, deem it safer in general, not to apply non‐cyclic corrections by Chree's method, with all the suppositions it implies, e.g., progressive linear change throughout the day, but we are quite ready to give all the information in our observatory publications which others may require for any procedure they may make themselves responsible for. Fortunately in terrestrial magnetism the “non‐cyclic” correction, as derived from differences of successive midnight values, is, in general, small, however, the case is entirely different in atmospheric electricity where the accidental or disturbing features may play a predominant part. We have repeatedly determined the Fourier coefficients from a series of diurnal‐variation observations extending over several months, or over several years, and have invariably found that the differences in the essential quantities, computed with or without application of a supposed non‐cyclic correction, are inconsequential from a physical standpoint.
The upper atmosphere
Authors: Maris H. B.
Published: February 2008

Wind Currents and Diffusion—The components of a uniformly mixed atmosphere kept free from winds would separate by diffusion, heavier molecules moving down and light molecules moving up. The flow of separation would be uniform at all heights; for example, in the air 1.07×108 molecules of helium would be expected to move up past any horizontal square centimeter per second. This upward flow of the helium would establish gravity equilibrium for helium gas above 140 km in one day, above 120 km in five days and above 106 km in fifty days. Wind‐currents, it is estimated, would cause a movement of the air above 100 km to lower altitudes once in five to twenty‐five days.

Temperature of the Upper Atmosphere—Radiation and absorption coefficients lead us to expect a temperature change of approximately 140° C between day and night during the summer and 30° C during the winter, at a height of 80 km. Carbon dioxide is found to be more important than water‐vapor in determining the radiant energy which escapes from the Earth's outer atmosphere, and the conclusions are reached that the ice‐ages can be explained by slight changes in the carbon‐dioxide content of the air.

Density of the Upper Atmosphere—New tables of density are compiled which show helium‐content and hydrogen‐content roughly 1/100,000 of those previously calculated for heights greater than 130 km. The conclusion is reached that above 300 km the atmosphere can not be assumed to be in a state of equilibrium, but that the percentage of very high‐energy molecules would be far higher than would be given by a Maxwellian curve for thermal equilibrium.
Ueber die magnetische Eigenschaft von Gesteinen
Authors: Koenigsberger J. G.
Published: February 2008

The topographical magnetic effects in the Alps and in the Black Forest are given approximately by the magnetic induction calculated from the observed susceptibility; the same is true according to Carlheim‐Gyllensköld for anomalies caused by the magnetic ore of Lapland. But Folgheraiter, Brunhes, David, and Chevallier could explain their observations only by remanent magnetization of the rocks studied. The author has therefore studied this question and found that all rocks have remanent magnetization, induced during cooling between 450° and 600° C, which is for intrusive igneous rocks about 0.2 to 0.8 of the induction (Jk] calculated from the observed susceptibility and the total intensity at this time. Many intrusive rocks, especially lavas, have a higher ratio—from 1 to 10. This high ratio must be explained by a remanent magnetization near saturation and a large coercive force; the available inductive susceptibility at 20° C is now smaller, than was the corresponding susceptibility at the higher temperature above 400°. The variability of this ratio suggests a variability of some physical conditions, for example, movements, during the time of cooling at the temperature at which magnetization becomes rémanent. The average influence of the remanent magnetization of intrusive and of many extrusive rocks at some distance is often very small, while the direction of the magnetization is changing rapidly, as was proved by measurements on different rocks. The absolute value of susceptibility (K) and of the remanent magnetization (J) is often not constant in a cube of 4‐ to 7‐cm edge. This inhomogeneity u1, u2, U3 and the anisotropy a1, a2, a3 were also measured for the three directions of a cube of the rock.
A new theory of magnetic storms
Authors: Chapman S. , Ferraro V. C. A.
Published: February 2008

6—The phenomena accompanying the advance of a solar ionized stream into the Earth's field.

6.1—A stream of particles emitted nearly radially from an active area A on the Sun will have a curved form, on account of the Sun's rotation. The stream will lag slightly behind the solar radius through the emitting area A though each particle of the stream will move almost rectilinearly, approximately along the solar radius through the position of A at the instant of emitting that particle. The rate at which the lateral surface of the stream will approach the Earth, overtaking it in its orbital motion, depends only on the Sun's known angular velocity; the point of intersection of the Earth's orbit with the lateral surface of the stream moves relative to the Earth with a velocity of about 400 km/sec, thus traversing a distance equal to one Earth‐radius in about 18 seconds. If undisturbed by the Earth's field the stream would sweep across the Earth in about 35 seconds.
Measurements of total nuclei, of uncharged nuclei, and of large ions in the free atmosphere at Washington, D.C
Authors: Torreson O. W. , Wait G. R.
Published: February 2008

In July and August, 1931, observations were made on the total and uncharged condensation‐nuclei in the free atmosphere on the grounds of the Department of Terrestrial Magnetism of the Carnegie Institution of Washington, in northwest Washington. The nuclei were measured before and after passing through a large‐ion counter between the tubes of which sufficient potential was applied (about 900 volts) to remove all charged nuclei with mobility of 1/3000 cm per second per volt per cm. From 21 sets of measurements, the ratio of uncharged to total nuclei (N0/NA) is found (after applying corrections for loss of nuclei while passing through the apparatus) to be 0.66, the mean value of N0 being 6,300 and the computed value of NA being 9,500. With potentials of 535, 890, and 1890 volts interchanged on the large‐ion tubes, practically no change occurred in No/NA, showing the mobility of the large ion to be not less than 1/1700 cm per second per volt per cm.

In October and November, 1931, 77 measurements were made with the large‐ion counter on the number of electronic charges of one sign (positive and negative alternately) per cc in the atmosphere, simultaneously with measurements of total and uncharged nuclei. Small ions were removed from the air entering the large‐ion counter by a small‐ion counter attached to the intake. From these data N0/NA is 0.72, N±/NA is 0.14, N0/N± is 5.8 and the charge per large ion 1.10, the last figure being in good support of the generally accepted view that each large ion carries only one electronic charge. It is seen that NA = N0 + 2N±. The values of N0 and NA are more than double those found in July and August, being 15,000 and 21,000 nuclei per cc, respectively. These results are compared with the work of J. J. and P. J. Nolan, Scholz, Hess, and Israël, and evidence is found for believing that the ratio N0/NA increases in magnitude with increasing nuclei‐content of the air.

A quite different analysis of the data obtained in October and November than was made for the above results is undertaken on the basis that N±/NA is not 0.14 but has instead two values, since 23 individual values fall closely around 0.20 and the remaining 54 around 0.10. The immediate conclusion is that the nuclei are at times doubly charged. From this point of view, the data are retabulated and re‐examined and it is found that the results do not show any inconsistencies which would preclude the possibility that doubly‐charged large ions were present almost exclusively on certain occasions and singly‐charged ones almost exclusive on other occasions during the observations here discussed.
Huancayo Magnetic Observatory October to December, 1933
Authors: Cairns J. E. I.
Published: February 2008

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

There were no marked disturbances during October to December, 1933.
THE LARGE‐ION AND SMALL‐ION CONTENT OF THE ATMOSPHERE AT WASHINGTON, D. C.
Authors: Wait G. R. , Torreson O. W.
Published: February 2008

By means of automatic recorders, the small‐ion and large‐ion content of the atmosphere at Washington, D. C., have been secured. The number of large‐ions have been continuously recorded over a period of nineteen months and the small‐ions over a period of twelve months. Curves of diurnal variation of large ions and of small ions for the various months of the year are drawn. During the cold season of the year, the large ions pass through maxima in the morning and in the evening. During the warm season, only the evening maximum is present which shows a seasonal variation in time of occurrence. The small‐ion variation through the day is more or less reciprocal to the large‐ion variation, but is considerably smaller when regarded on a percentage basis. This is largely attributable to the fact that a portion of the current in the small‐ion counter is contributed by intermediate ions present in the atmosphere. The large ions and relative humidity vary directly during the cold season and in an inverse manner during the warm season. This change in character from one season to another will be a contributing factor to the daily and yearly changes that occur. The mobility of the large ions, as determined in this investigation, is noticeably greater than that ascribed to them by Langevin, thus indicating that the ions in the two places are not identical in size, unless the difference may be attributed to a difference in experimental conditions.
The electricity of rain and thunderstorms
Authors: Gunn Ross
Published: February 2008

Electricity of rain: It is shown that the observed properties of rain‐drops of very different histories are readily described if each water‐droplet and the surrounding ionized water‐vapor is considered an electrical concentration‐cell. The potential difference between the drop and points several radii outside approximate 0.06 volt. The equilibrium‐charge on each droplet is proportional to the radius and is positive if the droplet is evaporating and negative if it is condensing. These droplets grow by association into large rain‐drops and thus build up large charges of the order of 1/50 e.s.u. which discharge by conduction in a time of the order of 103 seconds. The drops thereafter take on an equilibrium‐charge depending upon the evaporation or condensation of the drop and its size. The calculated charges are in agreement with observation. A laboratory experiment verifying certain aspects of the predicted effects is described.

A theory of thunderstorm‐electricity: It is shown that in the presence of a rapidly rising current of air and the formation of rain‐drops greater than a critical size, separation of charge takes place. At levels of condensation the atmospheric ions (usually positive) are swept to great heights while the newly‐formed rain (usually negative initially) falls. Both charge‐distributions discharge by conduction at different rates, leaving the charge in the zone of rain‐formation in excess (usually negative). The excess charge induces charges on the Earth or on the high conducting atmosphere of a magnitude equal to a large fraction of the excess charge. Rain‐drops formed by the association of droplets below the saturation‐level impart a normally positive space‐charge to the region. The charge‐distribution resulting from the separation is quantitatively calculated from physical data and agreement obtained with observation in regard to the potential differences, electrical field, electric moment, charging current, recovery‐time, and the average charge on the precipitated rain.

Maintenance of the Earth's charge: Some objections to Wilson's thunderstorm‐theory of the maintenance are noted. It is shown that special thunderstorm‐conditions in mountainous regions are such that a total storm‐area of 0.01 per cent of the Earth's surface would precipitate sufficient negative charge on rain and transfer enough positive charge upward by convection to maintain the field. The possible importance of forced vertical convection over natural barriers in “fair‐weather” regions is considered and it is shown that such a systematic convection may account for an appreciable part of the necessary replenishing current.

Distribution of free space‐charge: The factors determining the free space‐charge are considered and the resulting distribution of charge, electric field‐intensity, and potential are found.
The local variation of the Earth's electric field
Authors: Brown Joseph G.
Published: February 2008

Assuming that local diurnal‐variations are small over the oceans, and absent over the polar ice during the winter night, a curve has been adopted which represents the unitary diurnal‐variation for a mean ocean‐field of 129 volts per meter. The unitary variation at each land‐station has been found by multiplying the ocean‐variation by the ratio of the mean land‐gradient at each station to the mean ocean‐gradient. By subtracting these unitary variations from the observed mean curves the local diurnal‐variations have been obtained for 22 stations. Each local variation‐curve has been resolved into a 24‐hour component and a daytime depression‐component. The stations fall into groups according to latitude, and the mean latitude‐stations are of two types depending upon the amount of pollution. A theory is proposed which shows the significance of the components and accounts for the local diurnal‐variation by the cycle of turbulence, convection, and subsidence which is present at all land‐stations on all clear days.
On the diurnal variation of the cosmic radiation
Authors: Hess Victor F. , Graziadei H. Th.
Published: February 2008

A final account of a series of observations of the cosmic‐ray ionization on the Hafelekar (2300 meters above sea‐level) covering three years (1932, 1933, and 1934) with about 20,000 hourly values obtained with Steinke's standard apparatus at constant temperature, is given. The existence of a regular diurnal variation of the cosmic‐ray ionization according to local time (Middle European Time) is proved. Its amplitude amounts to ±0.2 percent of the total ionization; the maximum occurs at noon, the minimum between 21h and 3h M. E. T. A discussion of the possible causes of this variation is given. It must be ascribed to an indirect or direct solar influence upon the intensity of the cosmic‐ray ionization.
Geomagnetic coordinates for the entire Earth
Authors: McNish A. G.
Published: February 2008

During a recent investigation it was found necessary to construct a system of geomagnetic coordinates covering the entire Earth. As these may be found useful to those engaged in terrestrial‐magnetic, cosmic‐ray, and other geophysical researches for finding the geomagnetic coordinates of various places the nomographs prepared are reproduced herewith.

Many magnetic phenomena are frequently found to have a relatively simple distribution when consideration is given to the location of the observing stations relative to the pole of the first‐degree harmonics of the Earth's general magnetic field. A coordinate‐system having this pole as its origin is called a system of geomagnetic coordinates. The term magnetic coordinates is sometimes used to denote this system but as magnetic coordinates are sometimes considered as deducible for a point from the magnetic elements at that point the former term avoids ambiguity in considering those based upon the general field. Thus, the magnetic meridian at a point is defined by the declination at that point, the magnetic latitude by the inclination—the tangent of the magnetic latitude being half the tangent of the inclination—while the geomagnetic meridian is the portion of the great circle joining the point to the pole of the first‐degree harmonics and the geomagnetic latitude is the complement of the angular distance along that circle to the pole.
Relationship between auroral and magnetic activities at Little America, First Byrd Antarctic Expedition 1928–30
Authors: Ennis C. C.
Published: February 2008

Instead of correlating coincident values of auroral intensity and of magnetic declination only, as was done in a prior investigation by the author, use was made of corresponding values of horizontal intensity also. The “disturbing force” (amount and direction) was computed for each half‐hour during the day for June, July, and August (incomplete) from “normal‐day” departures of observed values of declination and horizontal intensity. The results were classified according to the presence or absence of auroræ. Represented by a series of graphs, they show interesting contrasts and similarities with respect to the two classes. Of special note is an outstanding post‐midnight maximum in the disturbing force, occurring consistently, from the standpoints of time and magnitude, but only when auroræ were present and at a time of day when auroral intensity was at about its daily minimum. Another feature revealed by vec ordiagrams of the disturbing force is the two‐loop, day and night characteristic.
A new type of vertical‐intensity induction‐variometer
Authors: McNish A. G.
Published: February 2008

A new type of vertical‐intensity induction‐variometer is described. Extensive tests reveal that it is free from the faults inherent in the older style balance type instruments. The theory of its operation and other possible applications are discussed.
Characteristics of the upper region of the ionosphere
Authors: Berkner L. V. , Wells H. W. , Seaton S. L.
Published: February 2008

Operation of stations making observations of the ionosphere in widely separated locations over the Earth's surface by the Department of Terrestrial Magnetism, Carnegie Institution of Washington, has produced data of unusual interest. Values of critical frequency of penetration and minimum virtual‐height for theF2‐region are now available from Washington, D.C., U.S.A., Huancayo, Peru, and Watheroo, Western Australia, for periods ranging from one to six years. These data are presented in the form of monthly averages of noon values. It is shown that noon values are a measure of conditions during the daytime hours. The average noon values of critical frequency for theF2‐region are found to have similar characteristics in both hemispheres, reaching a maximum from about November to February and a minimum from about May to August, at stations in both the Northern and Southern hemispheres simultaneously. This leads to a strong presumption that this variation is, predominantly, an annual effect. The simple hypothesis of thermal expansion of the upper atmosphere, which has been evolved by other investigators to account for the effects observed in the Northern Hemisphere alone, will not explain these critical‐frequency phenomena, observed in both hemispheres simultaneously. In this respect, therefore, it must be radically revised or discarded.

Average minimum virtual‐heights of this region observed at noon show that at Washington and at Watheroo these heights change inversely with the noon zenith‐angle of the Sun, while at Huancayo, they change directly with the noon zenith‐angle. This reversal in character in equatorial regions is considered. It is possible that these effects may be explained by a new hypothesis of thermal movement of the upper atmosphere, considering the forces imposed upon the motions of the ions in the Earth's magnetic field.
The bright hydrogen eruption and radio fade‐out of April 8, 1936
Authors: Richardson R. S.
Published: February 2008

Special solar observations were made at Mount Wilson from October 21 to 251 and from December 14 to 18, 19352, in connection with the high‐frequency radio transmission fade‐outs which have been observed to occur at intervals of roughly fifty‐four days or multiples thereof. Attention was first called to these fade‐outs by Dr. J. H. Dellinger3, radio chief of the National Bureau of Standards. Continuously cloudy weather at Mount Wilson from February 10 to 19, 1936, prevented observations at the time of the fade‐out on February 14, which was particularly striking and reported by observers in many places. Consequently it was planned to repeat the special observing program from April 6 to 10, inclusive, which consists in taking hydrogen spectroheliograms as rapidly as possible with the hope of photographing a bright eruption which might be associated with changes in radio transmission.
New results of cosmic‐ray research
Authors: Hess V. F.
Published: February 2008

Continuous registrations of the cosmic‐ray ionization by Steinke's standard apparatus at elevations above sea‐level of 2300 and 600 meters (Hafelekar and Innsbruck) kept at constant temperature from 1931 to 1934 and in 1936 have brought interesting results. Among these, for instance, the existence of a regular, small diurnal variation according to solar time has been established1.

Recently one of my collaborators, W. Illing,2 tested the existence of diurnal variation according to sidereal time as postulated by A. H. Compton's theory of the extra‐galactic origin of the cosmic radiation. The curve derived from 21,000 hourly observations in three years showed a certain resemblance to Compton's theoretical curve, which however disappeared when all observations were reduced to the same outdoor temperature.
Influence of pollution on potential gradient at Apia
Authors: Sapsford H. B.
Published: February 2008

The general results of research on the diurnal variation of potential gradient lead to the conclusion that its form at any station is due to a local variation superimposed on the single universal‐time oscillation which was discovered by S. J. Mauchly [see 1 of references given at the end of the paper]. It has been pointed out that the local variation in the potential gradient must be due to changes in the atmosphere immediately surrounding the station [2]. Further it has been agreed that the conductivity is the chief factor in determining the gradient. J. G. Brown has also suggested that the conductivity at any time is dependent, in turn, upon the formation of small ions and the number of nuclei present at that time, the latter being a greater cause of variation in the conductivity than the former.
Interference with telegraph service during latter part of January 1938, caused by magnetic storm
Authors: Willever J. C.
Published: February 2008

The following report from the Traffic Department of the Western Union Telegraph Company gives information on the severity and extent of interference with service during the latter part of January caused by the magnetic storm associated with Aurora Borealis:

“While there was some interference noted on the circuits up and down the Pacific Coast, the maximum interference occurred elsewhere throughout the country, the transcontinental circuits being most seriously affected. The disturbance started on January 22, at which time the interference was comparatively slight, and gradually increased in intensity until the afternoon of the 25th, when maximum readings in excess of 400 volts were recorded in many parts of the country.
On cosmic‐ray effects associated with magnetic storms
Authors: Forbush S. E.
Published: February 2008

Evidence indicates that the storm‐time field of some magnetic storms causes world‐wide changes of several per cent in cosmic‐ray intensity. That other magnetic storms of equal intensity at the Earth's surface occur with no appreciable cosmic‐ray effects definitely indicates that the entire current‐system for the storm‐time field of both types of storms can not be located at the same distance above the Earth. In particular, the possibility that the current‐systems responsible for the two types of storms both lie within the Earth's atmosphere appears remote. Assuming the current‐system for the storm‐time field of both types of storms to consist of a ring concentric with the Earth in the geomagnetic equatorial plane, magnetic data are analyzed to determine whether the radius of the assumed ring is, as would be expected, greater for magnetic storms which affect cosmic‐ray intensity. Although the analysis is not conclusive on this point, the results satisfy a necessary condition for the existence of such a ring‐current. The occurrence of aurora in temperate latitudes during most of the magnetic storms which affected cosmic‐ray intensity is interpreted, after Störmer, to indicate the existence of such ring‐currents. The percentage‐changes in cosmic‐ray intensity during magnetic storms is within the observational uncertainty the same at geomagnetic latitudes 50°.1 north and 0°.6 south. The significant correlation between changes in daily means of cosmic‐ray intensity, for two stations separated 50° in latitude, probably results from the same mechanism responsible for the magnetic‐storm effect.
Magnetization of unmetamorphosed varves and marine sediments
Authors: McNish A. G. , Johnson E. A.
Published: February 2008

Introduction—Knowledge concerning the range of its variation is essential to an understanding of the Earth's general magnetic field. Clearly, if, as some claim, the Earth's magnetic field has been completely reversed in past geologic ages our notions of its origin, and perhaps our entire conception of the Earth's interior, must be radically revised. On the other hand, if it can be shown that the Earth's general magnetic field is a rather static phenomenon and that the observed secular changes involve only a superficial portion of the field other types of causes are suggested.

Direct observations of secular variation extend over four centuries at a few places on the surface of the Earth. Although some of the changes have been very large they suggest cyclic variations rather than continuous variations in one direction. Some of the more remarkable of these changes are a shift in declination from 11° east to over 24° west at London from 1600 to 1800, a decrease of 5900 gammas in horizontal intensity at Capetown from 1843 to the present time, and a decrease of 6000 gammas in vertical intensity off the Guinea Coast from 1885 to 1922. If changes as great as these have occurred in modern historic times how great have the changes been in thousands and millions of years of prehistory?
Blue auroral rays situated in the sunlit part of the atmosphere
Authors: Störmer Carl
Published: February 2008

§ 1. The blue sunlit auroral rays on March 23, 1920—Since my permanent auroral stations in southern Norway were established in 1911, sunlit auroral rays have been observed and measured about 50 times, but among these, blue ones have occurred only on two occasions, the first March 23, 1920, and the second September 15, 1938, both before sunrise.

A report on the blue rays of March 23, 1920, is given in a paper covering the period 1911‐1922.l From this paper we quote the following description:
The theory of the first phase of a geomagnetic storm
Authors: Chapman S. , Ferraro V. C. A.
Published: February 2008

An exact solution is given (apart from the neglect of displacement‐currents) for the motion and electromagnetic fields of a uniform neutral ionized distribution of ions and electrons initially situated on an indefinitely long circular cylindrical surface, and projected radially inwards towards the axis of the cylinder, in the presence of a permanent magnetic field which is everywhere parallel to the axis, and varies in intensity as the inverse cube of the distance from the axis. It is shown that the ions and electrons will remain “united,” that is to say, will continue to lie on one cylindrical surface, if the total ionic (or electronic) charge exceeds a certain lower limit; an electric current will be induced, flowing round the cylindrical surface and increasing the magnetic intensity within the cylinder. The problem is discussed as one which partly illustrates the first phase of a magnetic storm, and, in particular, the sudden increase of H, during only a few minutes; it clearly shows that when a neutral ionizing stream advances into regions of increasing intensity in a magnetic field, the electrostatic attraction between the ions and electrons can carry the electrons forward far beyond the distances they could attain alone, if the stream is sufficiently dense.
Spherical harmonic analysis of the Sq‐variations, May‐August 1933
Authors: Benkova N. P.
Published: February 2008

§ 1. The present paper gives the results of the spherical harmonic analysis of the quiet solar diurnal variations (Sq) of the Earth's magnetic field for the summer months, May to August, 1933. Schuster [see 1 of “References” at end of paper] was the first to apply in 1889 Gauss's expansion in terms of spherical harmonics to the analysis of diurnal variations. The spherical harmonic analysis of the Earth's permanent and transient magnetic fields is of the utmost importance, first, because it permits generalizing the empirical data in the form of an analytical expression and, second, because it offers information regarding the structure of this field (its potential and its origin). The spherical harmonic analysis of the diurnal variations has therefore been repeatedly undertaken by many investigators [2 to 7]; but from time to time, with accumulation of new observational data (of greater reliability, or referring to other epochs), it becomes desirable to have recourse to new analyses.
Tucson Magnetic Observatory, January to March, 1941
Authors: White Roland F.
Published: February 2008

March 1–3—A severe storm began at 03h 57m GMT, March 1, with an increase in H of 74 gammas in three minutes. The variations were large and rapid. At about 16h the H‐reserve spot went off scale negative for a range in H in excess of 550 gammas. The range in D was about 50′.
Cheltenham Magnetic Observatory, April to June, 1941
Authors: Ludy Albert K.
Published: February 2008

April 18–20A storm began at 19h 06m GMT, April 18, and ended April 20 at 09h 30m. The storm was characterized by long‐period oscillations between 04h and 11h, April 19. The highest K‐number was 6. Ranges: D, 38′; H, 96 gammas; Z, 113 gammas.
Hermanus Magnetic Observatory, January to June, 1941
Authors: Ogg A.
Published: February 2008

January 1—The period from 12h to 18h GMT was moderately disturbed.

January 5–9—A storm began with a small commencement at 15h 45m GMT, January 5, with an increase of 11 gammas in H in four minutes. The storm continued until 0lh, January 7. There were further disturbances on January 7 in the period from 15h to 21h and on January 9 from 12h to 15h. The ranges of H we re of the order of 70 gammas.
Geomagnetic bays, their frequency and current‐systems
Authors: Silsbee H. C. , Vestine E. H.
Published: February 2008

Birkeland [see 1 of “References” at end of paper] has made extensive studies of the field and current‐systems of bays, using data for magnetic stations of the Polar Year, 1882‐83, and less complete data for other years. In these important investigations he deduced considerable information respecting the geographical distribution of their fields and current‐systems. He suggested that the polar part of the current‐system in all probability flowed in (or beyond) the Earth's atmosphere with greatest concentration of current near the auroral zones at heights of 100‐700 km.

Birkeland's supposition of an intake and outflow of current directly to or from the auroral zones has been shown to be somewhat doubtful and improbable as a consequence of later calculations of Vestine and Chapman [2]. His findings, however, in the main have been confirmed, although notably extended and to some degree reshaped in later valuable discussions by Steiner [3], Wiechert [4], McNish [5], Chapman and Bartels [6] and Hatakeyama [7].
Association of large ions and fog
Authors: Phillips Marcella Lindeman
Published: February 2008

During the course of another investigation in which large ions were being measured by means of the large ion‐counter of the Department of Terrestrial Magnetism [see 1 under “References” at the end of paper] an abnormally high large‐ion count was noted during the night of December 3–4, 1941. The sudden rise in count preceded a widespread fog along the North Atlantic Coast, reported as being the worst in the past five years.

Comparison of the ion‐count record with the record of visibility observed at Boiling Field (Table 1) showed that the concentration of large ions had risen to an unusually large value about seven hours before the fog set in, decreased during the fog, and increased to a large value again after the disappearance of the fog. Another dense fog formed during the next day but, unfortunately, no ion‐measurements were made at this time.
Variation of the Sun's ultra‐violet radiation as revealed by ionospheric and geomagnetic observations
Authors: Allen C. W.
Published: February 2008

Summary—A study has been made of the short‐ and long‐period variations of critical frequencies of the E‐, F1‐, and F2‐ionospheric layers at Washington, Huancayo, Watheroo, and Mount Stromlo during 1937–44. Terrestrial factors have been eliminated in order that the frequencies should represent the changes in the ionising ultra‐violet light. A similar study has also been made of the variations in the amplitude of the Sq magnetic field at Apia, Watheroo, and Cape Town during 1937–43. Yearly, monthly, and daily variations have been compared with solar data by means of graphs and correlation‐methods. The following are the main conclusions:

(a) The variable part of the Sun's ultra‐violet illumination comes mainly from active regions characterised by the appearance of sunspots, flocculi, and faculae.

(b) The sources of ultra‐violet have a longer life than sunspots, and possibly a longer life than faculae.

(c) The three ionospheric layers E, F1, and F2, and the Sq‐field are influenced by the same sources of ultra‐violet light.

(d) The sources emit considerable ultra‐violet radiation when at the center of the Sun and probably emit some radiation when near the limb.

(e) F2 electrons take periods of one or two days to reach equilibrium concentration —at the level of Sq‐currents recombination is much more rapid.

(f) The variable part of the ultra‐violet flux is proportional to sunspot‐number, and is about equal to the steady part at sunspot‐maximum. This applies to radiation exciting the E‐, F1‐, and F2‐regions.

(g) There is a linear relation between f0F2 and sunspot‐number.

(h) Faculae could produce continuous ultra‐violet radiation that might account for ionospheric and geomagnetic variations.
Hermanus Magnetic Observatory January to March, 1946
Authors: Ogg A.
Published: February 2008

(Latitude 34° 25′.2 S., longitude 19° 13′.5 or 1h 16m.9 E. of Gr.)

January 3–4—A magnetic storm started suddenly (H increased 30 gammas in three minutes) at 08h 10m GMT, January 3, and continued for about 35 hours. The ranges of the storm were as follows: H, 218 gammas; D, 3′.7 ≡ 129 gammas; Z, 185 gammas. After about 22h the form of the magnetic activity was slow oscillations with three large bays, each of magnetic activity K = 4, from 15h–24h, January 4. The greatest magnetic activity of the storm was K = 6 for each of the three‐hour periods 09h–15h, and K = 7 for the period 15h–18h, January 3.
The auroral luminosity‐curve
Authors: Harang Leiv
Published: February 2008

The theoretical curve of luminosity produced by a bundle of cathode rays penetrating an atmosphere rectilinearly is discussed. The auroral luminosity‐curve is determined by photographic photometric methods. The luminosity‐curves observed are compared with the theoretical luminosity‐curve produced by cathode rays. The value of H = (kT/mg) is determined as a function of height of the maximum of luminosity. The values of H determined from studies of auroras are in agreement with the values determined independently from ionospheric studies. From filter photographs the values of H are determined independently for the luminosity in green (G) and violet (V).

Using the experimentally determined values of H the density and pressure in the auroral region for various heights are computed. The curves of absorption and of luminosity for bundles of cathode rays in the range of velocities from 0.02 c to 0.9 c penetrating the model atmosphere rectilinearly are computed. The height of the anormal E‐reflections observed during auroral displays and the position of the absorbing layer are discussed.
The sunspot‐cycle before 1750
Authors: Schove D. Justin
Published: February 2008

Sunspot‐numbers since 1749 form [Wolf, 1945] a long and reliable series of indices with an obvious but unexplained 11‐year cycle (see Fig. 1). Harmonic analysis has hitherto proved unsuccessful in extending the series forward into the future. Even the first decimal place of the length of the cycle is in dispute and it has been suggested that at times a ten‐year or smaller cycle replaces the normal one (compare Zeuner, 1946, p. 16, etc.) The predictions of 25 years ago are already out of phase with actuality and, even as regards the immediate future, experts disagree.