bluuebunny/crossref_metadata_2025 huggingface dataset:
Huancayo Magnetic Observatory January to March, 1935
Authors: Torreson O. W.
Published: February 2008

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

January 27–28—This storm, of comparatively short duration, is conspicuous not only for a sudden commencement in all three elements, but also for two subsequent sudden and large changes in H. The sudden commencement occurred at 14h 49m, G. M. T., with an increase, within a period of five minutes, of 105 gammas in II, an increase of 4 gammas in Z and an increase of 2′ in D. There followed minor peaks and bays in H, while D and Z were little disturbed, until 18h 17m. Then, in six minutes, H decreased 102 gammas, Z decreased 3 gammas, and D first increased 1′ and then decreased 2′. Again, from 19h 46m to 19h 50m there was a sudden decrease in H of 71 gammas, and of 1′ in D, but no effect in Z. Thereafter H, showing various peaks and bays, remained lower than normal for several hours, reaching a minimum at 0h 58m on January 28 then gradually recovering to normal values by 12h. Between 12h and 22h on January 28, various small peaks and bays were superposed on the normal diurnal trend. D and Z were little disturbed subsequent to the second sudden change described above.
On the principles of magnetic cartography
Authors: Weinberg Boris
Published: February 2008

The purpose of a magnetic chart is to represent graphically the distribution of one or several magnetic elements over a portion of the Earth's surface or over the entire surface of the globe. The variation of the element with altitude is rarely charted.

If the net of magnetic stations were sufficiently dense that an interpolation between the observed values of the element in question for points where no observations have been made, would involve no appreciable error, the magnetic chart could be considered as representing the true or real distribution of the element. Such an interpolation is justified only if we are sure that the survey has disclosed all places of extreme values—maxima and minima—of the element. But this applies only to very detailed microsurveys for which the mean distance between the extremes of magnetic elements is of the order one km1. Accordingly the great majority of magnetic charts represent the smoothed2 or normal distribution of the magnetic elements3.
The Warsaw meeting of the Commission of Terrestrial Magnetism and Atmospheric Electricity, September 1935
Authors: Laursen V.
Published: February 2008

The meeting opened September 2 but most of the members present, together with several others interested, had met September 1 for which day an excursion to the Swider Magnetic Observatory had been arranged. The Observatory with its installations and fairly complete instrumental equipment made a very favorable impression as did also the hospitable reception accorded the visitors by Professor Kalinowski and his family.

The official meeting was opened by the President, Professor Ch. Maurain, the following countries being represented by 17 members of the Commission, and other interested persons who attended the sessions and took part in the deliberations: Austria, Canada, China, Czechoslovakia, Denmark, East Africa, Finland, France, Germany, Great Britain, Holland, Italy, Japan, New Zealand, Norway, Poland, Spain, Sweden, and Switzerland.
Correlation of auroral and magnetic activities for different periods of the night at Chesterfield, Canada, 1932–33
Authors: Davies F. T.
Published: February 2008

In the September number of this Journal (p. 267), correlation of auroral and magnetic activities was discussed using the twelve‐hour night period as a basis. At the suggestion of Professor S. Chapman, correlation‐coefficients (r) have been worked out for three‐hour periods, to determine whether the high degree of correlation found for twelve‐hour periods obtained during different parts of the night. In the following summary of results IA and IM are mean auroral intensity and magnetic character‐number, respectively.

The correlation is good for all except the morning hours 3h to 6h. During these hours magnetic activity decreases more rapidly than auroral activity» The value of IA for the morning hours is as great as for the evening hours 18h to 21h, when conditions for observation of aurora are the same. It appears then that at this station, although auroral and magnetic activities are strongly associated during the greater part of the night, auroral activity continues into the morning hours when much quieter magnetic conditions prevail.
The theoretical calculations of the distribution of photochemically‐formed ozone in the atmosphere
Authors: Wulf Oliver R. , Deming Lola S.
Published: February 2008

The paper consists of a calculation of the distribution of ozone with height as it would be in an undisturbed photochemical steady state under the influence of solar radiation considered as that of a black body at a temperature of 6000°K. An expression is derived for the number of ozone molecules as a function of height, in terms respectively of a numerical constant, the concentration of oxygen and of total air molecules as a function of height, and the number of quanta absorbed by oxygen and by ozone as a function of height. The latter two quantities are in principle integrals over frequency‐ranges, and they are evaluated by summing over finite frequency‐strips. Moreover, the number of quanta absorbed by ozone at any height depends of course upon the concentration of the ozone itself. The complete expression is, therefore, evaluated by the method of successive approximations for a series of heights, the available intensity of the radiation absorbed by ozone being derived as the remainder from the last greater height. The ozone concentration, once evaluated for a particular height, is assumed constant over the interval of which this is the midpoint in evaluating the depletion of the radiation in this interval; then, by deduction, the remaining radiation available for the next lower interval is determined. The numerical constant is perhaps best looked upon as evaluated from the known total atmospheric ozone path, though its order of magnitude is indicated by the facts of experimental photochemistry. In this way a distribution of ozone is found which resembles rather closely that which from observation is now known approximately to obtain in the atmosphere. The values of the absorption‐coefficient of ozone and oxygen in the region where the two absorptions meet, that is, about 2200Å, prove to be very important, two possible sets of values being used in this narrow interval for illustration.
Short‐time magnetic fluctuations of local character
Authors: Vacquier Victor
Published: February 2008

The comparison of the short‐time fluctuations of the Earth's vertical magnetic intensity afforded by data taken during the daylight hours by the exploration troops of the Gulf Research and Development Company indicates that at points separated by 800 miles, 58 per cent of the fluctuations are of local origin. It is found that on a few magnetically quiet days, the time‐variations of the vertical magnetic intensity are locally so different in magnitude and in phase, as to condemn the theories of magnetic variations which are based solely upon the difference between night‐ and day‐ionization of the upper atmosphere. The observed irregularities are independent of magnetic activity. They can be accounted for only by the dynamo‐theory, and indicate the presence of local air‐circulations in the ionosphere. It is suggested that simultaneous registration of the magnetic elements at points spaced about five times the ionospheric height might delineate the circulation of the upper air, and thus provide perhaps information useful to meteorology.
The measurement of normal atmospheric‐electric potential‐gradients using a valve‐electrometer
Authors: Macky W. A.
Published: February 2008

An account is given of a valve‐method for measuring normal atmospheric‐electric fields. The apparatus was run for one month in an exposed position subject to all types of bad weather and functioned well throughout. No difficulty at all was experienced with insulation, and the apparatus as used with a string‐recorder gave a reliable record of fields up to about 400 volts per meter. By small alterations the range could have been increased or alternatively the apparatus made more sensitive for lower values. Comparisons with a radioactive collector and quadrant‐electrometer showed that the valve‐apparatus was unaffected by moist conditions which spoiled the insulation of the collector.
Cheltenham Magnetic Observatory October to December, 1936
Authors: Ludy Albert K.
Published: February 2008

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

October 9–10—A mild disturbance began about 7h 30m GMT, October 9. It continued until about 22h, October 10. The perturbations were irregular and not of great range. The more severe part of the storm was from 1h to 10h, October 10.
Magnetic and electric observations of the Drift‐Expedition to the North Pole
Authors: Fedorov E. K.
Published: February 2008

An important place in the program of work of the Expedition to the North Pole is given to the study of the magnetic and electrical phenomena. Absolute determinations of the magnetic elements will be made with Chasselon theodolite No. 87, adapted for measurements in high latitudes. The declination will be determined by the usual method, and the inclination by the Lamont‐method using rods of “dynamo” steel. Two pairs of rods of different sizes will secure a measurement of inclination up to 88°.
Note on Boris Weinberg's suggested magnetic nomenclature
Authors: Slaucitajs L.
Published: February 2008

With regard to Dr. Weinberg's suggestion in this JOURNAL (42, 214, 1937) I believe that it is unnecessary to change the term isopors of D, I, H, and Z to sallogons, isallolines, isallo‐H‐dynams, and isallo‐Z‐dynams. My proposal is to adopt in addition the term “isallopors” of D, I, H, and Z—to designate the lines of equal second differences of an element in time (change in secular variation, change in annual change). Studies of these second differences may be very important and it seems possible now in some cases to construct isalloporic charts. For instance, the data and isoporic maps of D of the United States of America constructed by D. L. Hazard (Trans. Amer. Geophys. Union, 11th Annual Meeting, 206–214, 1930) and others furnish material for the construction of isalloporic maps.
The long periodic variation in the diurnal range of magnetic horizontal component at Oslo Observatory
Authors: Wasserfall K. F.
Published: February 2008

As is known Hansteen began in the year 1843, a series of daily variaatlon‐observations of the magnetic elements in Oslo, which have been continued uninterrupted to the present time. Some years ago the author undertook to compile the entire material left by Hansteen and his successors, pertaining to observations of the horizontal component.

The material consists of two daily observations during 1843 to 1930; the readings were taken at 9h and at 14h local mean time. A large magnet, 1.2 meters long and weighing 13 kg is mounted by a bifilar suspension in the vault of the central hall of the Astronomical Observatory in Oslo. A small mirror, fixed to the magnet, reflects a divided scale mounted horizontally below a telescope which rests on a marble pier in the west wing of the building.
Ionization, negative‐ion formation, and recombination in the ionosphere
Authors: Bradbury Norris E.
Published: February 2008

The ionization in the ionosphere is discussed in the light of present theories of recombination and negative‐ion formation. It is suggested that the E‐ and F1‐regions are formed as the result of the absorption of special bands of solar radiation and that negative‐ion formation is the predominant process in these regions. A sufficient number of electrons exists, however, to cause the reflection of electromagnetic waves. The F2‐region is probably not due to the absorption of any special band of solar radiation but owes its formation to the preponderance at this elevation of electron‐positive‐ion recombination over negative‐ion formation during the day. The characteristics of the E‐ and F1‐regions are discussed quantitatively and compared with experimental observations. A qualitative discussion is given for the F2‐region since it seems probable that significant changes in level and density take place at these elevations.
Provisional solar and magnetic character‐figures, Mount Wilson Observatory, October, November, and December 1937
Authors: Nicholson Seth B. , Mulders Elizabeth E. S.
Published: February 2008

An exceptionally large active group in latitude 9° north crossed the solar disk from September 28 to October 10. It extended over an area about 20° long and 8° wide, and on October 4, when it crossed the central meridian, the center of the solar disk was within its boundaries. Following the large group were several other groups which with it formed a stream of spots over 100° long. Five magnetic storms, the first of which was reported in the last issue of the JOURNAL, occurred between September 30 and October 13. It is possible that all of these storms were due to the activity of the large group, although the other groups in the stream may also have had some effect.
On the lunar‐diurnal variation in the Earth‐currents
Authors: Egedal J.
Published: February 2008

In my article printed in this JOURNAL, June 1937 (pp. 179–181), the values given in Table 2 for the lunar variation of the earth‐current potential‐gradient during the solar hours 20 to 5 at Ebro Observatory for the year 1910 (direction 25° west of north) are to be corrected as follows:Hour Main term L2 in mv/km20 to 21 2.4 sin (2t+21°)22 to 23 2.4 sin (2t+7°)0 to 1 1.6 sin (2t+15°)2 to 3 1.2 sin (2t+355°)4 to 5 1.4 sin (2t+36°)

The value of L2 for the hours 20 to 5 is L2 = 1.8 sin (2t+15°) mv/km and for the day‐hours 6 to 19 is L2 = 2.2 sin (2t+44°) mv/km. The amplitude of L2 for the night‐hours is only a little smaller than that for the day‐hours and the phase‐angles for the two periods are not much different. As the amplitudes of L2 for both night and day are of good accuracy, it is evident that the amplitudes mentioned are not much different and it might seem desirable to reconsider theories on earth‐currents and earth‐current measurements.
Natural residual magnetism of eruptive rocks
Authors: Koenigsberger J. G.
Published: February 2008

§ 1. The apparatus for the measurement of remanence (Jrn, Jrs, Jrc) of magnetization JK and of susceptibility K of rocks [see sections “ Literature,” Part I and Part II] are of two kinds:

(a) Magnetometers, chiefly astatic [I, 1926c and 1927a, b, etc.], some showing a weak field at the position where the sample is placed, with compensation of the deflection, which requires a regular shape of specimen in measuring remanence or susceptibility [I, 1930c]; the sample may be put in a coil with a known magnetic field to measure JK for different values of H [I, 1930a, p. 273].
The electric current‐system of geomagnetic disturbance
Authors: Vestine E. H. , Chapman S.
Published: February 2008

I—Introduction

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

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

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

There has been published recently (August 1939) a volume on “Terrestrial magnetism and electricity” which is the latest and largest (778 pages) of a series 1 issued under the general title “The physics of the Earth.” All of them were prepared under the direction of committees of the National Research Council (U.S.A.); the first six volumes were published as Bulletins of that Council. The purpose underlying this scheme, initiated in 1926, was “to give to the reader, presumably a scientist but not a specialist in the subject, an idea of its present status together with a forward‐looking summary of its outstanding problems,” in view of the “considerable development of interest in geophysics, ... not. matched by the publication in English of systematic treatises on the subject” (Foreword).

In terrestrial magnetism and electricty the lack of such a treatise has been, and is, a decided handicap to American and British workers in the subject; I hope that the present war will not prevent the expected publication, this year, of the treatise “Geomagnetism” which has been in preparation since 1927, in collaboration (since 1929) with J. Barrels. It seems appropriate, if unusual, to refer to this forthcoming treatise in the present review, and to make some comments on the relation in which the two books will stand to each other. Certainly if their success is at all commensurate with the long period (over a sunspot‐cycle!) occupied by their preparation, English‐speaking geophysicists and physicists will gain an altogether new ease of access to the hitherto somewhat veiled arcana of earth magnetism and electricity.
The three‐hour‐range index measuring geomagnetic activity
Authors: Bartels J. , Heck N. H. , Johnston H. F.
Published: February 2008

Geomagnetic activity, the frequency and intensity of magnetic disturbance, is supposed to indicate the influence of solar corpuscular radiation on the Earth. Various schemes for measuring the fluctuations of this phenomenon are in operation, but in connection with direct ionospheric studies by radio methods it was found necessary to provide a new scheme using smaller time‐units than a day or half a day. A three‐hour‐range index K based on the “Potsdamer erdmagnetische Kennziffer” was therefore provisionally adopted by the International Association of Terrestrial Magnetism and Electricity, at Washington, D.C., U.S.A., in September 1939. Each collaborating observatory is to assign, to each three‐hour interval beginning at 0h, 3h, … etc. GMT, one of the integers 0 to 9 as range‐index K; their averages Km, carried to half‐units, express the new measure. Scales for K are determined by assimilation of frequency‐curves so that each observatory, within a year, for instance, has approximately the same number of intervals with K=0, or with K=1, etc. The principles and the practice of scaling K are described. The magnetic variations are regarded as superpositions of K‐variations (to be measured), and of non‐K‐variations (such as regular daily variations on quiet days, to be eliminated); this is illustrated by typical cases.

For January to June 1938, tables for K and Km are given based on eight observatories. From Km, daily indices B for 24‐hour intervals are derived, also equivalent ranges A. High correlations are found between K at the different observatories and Km. The effect of the persistence‐tendencies on these and other correlations is studied and provides examples of general interest in statistics. In general, the correlation‐coefficient r increases with the length of the time‐unit used; for instance, for the daily index B and the international character‐figure C, r is 0.95 for single days, but it reaches 0.98 for four‐day averages.

Incidentally, a geomagnetic solar‐flare effect was found preceding the outbreak of the intense storm on January 16, 1938; the time‐interval suggests 22 hours as an upper limit for the travel‐time of the solar corpuscles.
Main features of daily magnetic variations at Sitka, Cheltenham, Tucson, San Juan, Honolulu, Huancayo, and Watheroo
Authors: Bartels J. , Johnston H. F.
Published: February 2008

Uniform sets of graphs are given expressing the average daily magnetic variations at seven observatories as influenced by season, sunspot‐cycle, and magnetic activity. The effect of disturbance on the daily mean values of the magnetic elements is discussed. International disturbed days are shown to be more disturbed around Greenwich noon than during the rest of the day. This second‐order effect must be considered in studies of the disturbance‐field.
Analysis of local atmospheric‐electric phenomena at College, Alaska
Authors: Gish O. H. , Sherman K. L.
Published: February 2008

The atmospheric‐electric data obtained at College, Alaska, during the International Polar Year have been analyzed in order (1) to separate the universal and local features in their diurnal variation and (2) to compare them with the theory of the electrode‐effect. After eliminating the universal diurnal‐variation component from the potential‐gradient a local component remains. In winter this local component is largely the result of variations in the conductivity near the Earth's surface but in summer there is no correlation between these elements. The calculated ratio of the columnar resistance of the air over College to that over the oceans shows a diurnal variation. The statistical significance of this variation is questioned. If it is significant various hypotheses which could account for such a variation are considered.

The diurnal variation in positive conductivity retains its character throughout the year although its amplitude is about 50 per cent less in summer than in winter. Its variations are attributed chiefly to variations in q and N. In contrast the diurnal variation of negative conductivity changes markedly from summer to winter. The negative conductivity depends greatly on the field in winter whereas in summer the increased wind or factors closely associated with it effectively oppose the action of the field.

The theory of the electrode‐effect is reviewed and amplified. Following the method of Scholz additional relations based on both the large‐ and small‐ion theory are developed so that a variety of conditions are covered. Some of the results are presented graphically for ease in comparing with these and other results. The air at College was very quiet in winter and apparently met this restriction of the theory for the results obtained then are shown to be in satisfactory quantitative agreement with the theory.
The Geomagnetic Ring‐Current: I— Its Radial Stability
Authors: Chapman S. , Ferraro V. C. A.
Published: February 2008

§ 1. Introduction—In our theory1 of geomagnetic storms, we attribute the main phase to a hypothetical electric ring‐current, with a radius
which is only a small multiple (Z) of the radius (a) of the Earth; the influence of such a ring on the variations of cosmic‐ray intensity has also been suspected. 2 In the original account of our theory we discussed,3 inter alia, the mode of formation of the ring, its size, density, current‐intensity, and rate of decay. We hope to supplement that discussion in a series of Notes; in this, the first, we assume the existence of the ring, and consider its radial stability. For mathematical convenience we idealize the problem by making it “cylindrical”; in this respect the present Note resembles our recent “Theory of the first phase of a geomagnetic storm,”4 which will here be referred to by the initials FP.
Three‐Hour‐Range Indices, K, For Twelve Magnetic Observatories, January to June, 1940
Authors: Johnston H. F.
Published: February 2008

The Association of Terrestrial Magnetism and Electricity of the International Union of Geodesy and Geophysics passed a resolution in regard to three‐hour‐range indices at its Seventh Assembly held in Washington in September, 1939. The resolution was as follows: That the cooperation of magnetic observatories be sought for a three‐year period in an international trial‐scheme for the provision of three‐hour‐range indices (K) to characterize the variation in the degree of irregular magnetic activity throughout each day, especially in order to meet the requests made by the International Union of Scientific Radio telegraphy and other bodies for information concerning the magnetic activity more detailed than the present daily magnetic character‐figures, and that this trial‐scheme should, for the period 1940 to 1942, replace the scheme for a numerical character‐figure.

In response to the circular letter of January 20, 1940, from Dr. J. A. Fleming, President of the Association of Terrestrial Magnetism and Electricity, 19 magnetic observatories are supplying indices beginning January 1, 1940. The indices from seven observatories for 1940 were published1 in the issue for March, 1941, of this Journal. Those from the other 12 observatories for the period January to June, 1940, appear herewith. The principles and practice of scaling K are described in the paper2 entitled “The three‐hour‐range index measuring geomagnetic activity.”
Solar and Magnetic Data, January to March, 1941, Mount Wilson Observatory
Authors: Nicholson Seth B. , Mulders Elizabeth Sternberg
Published: February 2008

A great magnetic storm, the most intense since that of March 24, 1940, began suddenly on March 1 at 03h 58m GMT. A complex sunspot‐group, Mount Wilson No. 8032, which crossed the central meridian on February 27.3 in latitude +16° was then 24° west. This spot‐group consisted of one penumbral area surrounding four or five umbrae, the preceding having S polarity, the following, N polarity. This is contrary to the usual order of polarities in bipolar groups of the present sunspot‐cycle. This group was much like that associated with the great storm of March, 1940, but had less than half the area.
Three‐Hour‐Range Indices, K, for Twelve Magnetic Observatories, July to December, 1940, and Summary for 1940
Authors: Johnston H. F.
Published: February 2008

K‐indices from 12 magnetic observatories for the second half of 1940 are published herewith. Those for the first half of 1940 were published1 in the issue for June, 1941, of this Journal and the indices from the seven American‐operated observatories for the year 1940 were published2 in the issue for March, 1941, of this Journal. In accordance with the wishes of Dr. J. Bartels, Director, Geophysikalisches Institut, Potsdam, who is Chairman of the Committee on Three‐Hour‐Range Index, the text of the circular letter of January 20, 1940, from Dr. J. A. Fleming, President of the International Association of Terrestrial Magnetism and Electricity, sent to all directors of magnetic observatories, is given as follows :

“At its assembly at Washington in September 1939, the Association of Terrestrial Magnetism and Electricity adopted a resolution as follows:
New Magnetic Character‐Numbers for the Polar Station Gjöahavn for 1904
Authors: Wasserfall K. F.
Published: February 2008

When the report on the results of the magnetic station at Gjöahavn1 was compiled, magnetic character‐numbers were included. The system used to derive these numbers did not yield values directly comparable with the international character‐numbers recently published by Van Dijk2. It seemed worthwhile, therefore, to compile new and more satisfactory numbers. Meanwhile absolute storminess tables for D, H, and V have been published3 and these furnish means to derive better character‐numbers.
The Ionosphere at Huancayo, Peru, April to June, 1941
Authors: Ledig P. G. , Coile R. C. , Jones M. W.
Published: February 2008

This report is a continuation of those already published in this Journal1 and gives monthly mean hourly values of the heights and penetration‐frequencies of the ionospheric regions as obtained from the automatic multifrequency ionospheric recording apparatus located near Huancayo, Peru, South America, in latitude 12° 02′.7 south, longitude 75° 20′.4 west of Greenwich, which operates over a frequency‐range 0.516 to 16.0 Mc/sec. A complete discussion of these data will be made in an annual summary.

Table 1 gives the monthly mean hourly values of the actual heights of maximum electron‐density (hmax), uncorrected for retardation in lower regions2, and the minimum virtual height (hmin) for both the F1‐ and F2‐regions, the penetration‐frequencies for the E‐, F1‐, and F2‐regions, and the lowest frequency at which echoes were observed when that frequency was greater than 0.516 Mc/sec.
Results of Magnetic Observatories in Mexico, May, 1941
Authors: Gallo Joaquín
Published: February 2008

Table 1 gives the results obtained by Sr. A. Vaca Alatorre at secular‐variation stations Oaxaca and Puebla and at a new station Tehuacán. The instrument used was magnetometer‐inductor 107 (C. I. W. type) and the values are corrected to international magnetic standards.
Tucson Magnetic Observatory, April to June, 1941
Authors: Nelson J. H.
Published: February 2008

April 24–26—A moderate storm began at 07h 10m GMT, April 24, with long‐period fluctuations. The major activity ended at 10h, Ap il 25, though small fluctuations continued until 11h, April 26. Ranges: D, 19′.5; H, 200 gammas.

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

Ionospheric characteristics at the Huancayo Magnetic Observatory (12° 02′.7 south, 75° 20′.4 west) of the Department of Terrestrial Magnetism, Carnegie Institution of Washington, during the year 1940 have been published in quarterly reports in this JOURNAL [see 1 under 1 “References” at end of paper]. The present paper is a summary of reports on the data of 1940 and is the third of a series of annual papers summarizing ionospheric conditions at Huancayo [2]. Photographic records have been obtained with multifrequency equipment sweeping over a frequency‐range of 16.0 to 0.516 Mc/sec every 15 minutes continuously for 24 hours each day since December, 1937.

This paper continues the method of presentation used in the annual summaries for 1938 and 1939 [2]. Ionospheric characteristics are presented as contour‐maps illustrating mean diurnal variation in critical frequency, minimum virtual height, and height of maximum electron‐density for each region. Full lines are contours of frequency or height and dotted lines represent the curve of mean data for the month indicated. These figures afford an effective means of distinguishing general characteristics and month‐to‐month trends by casual inspection.
Investigation of Height of Local Magnetic Anomaly at Port Snettisham, Southeastern Alaska
Authors: Gebhardt R. E.
Published: February 2008

Introduction—During the past few years the demands upon the United States Coast and Geodetic Survey .for reliable aeronautical charts has greatly increased owing to the number of. small privately owned aircraft that have come into use. The owners of these planes demand more information regarding the local magnetic anomalies over the main traveled routes. The present charts show the isogonic lines for conditions encountered on the ground or the magnetic courses to important air‐ports. As the majority of these small planes are equipped only with a magnetic compass for cross‐country navigation, a knowledge of the effect of local and regional magnetic anomalies on these compasses has been desired. This investigation has been confined to a local anomaly existing in southeastern Alaska.
The Sunspot‐Group Associated with the Magnetic Storm of September 18, 1941
Authors: Richardson R. S.
Published: February 2008

If all intense magnetic storms could be as definitely related to a sunspot‐group as the one that began on September 18 about 04h 20m GMT, geophysicists would feel that one of their major problems was solved.

The group associated with this storm was first seen on the east limb on September 10 and was fully in view. the following day. It then consisted of two spots of moderate size in latitude 12° north. These developed rapidly into a large active group with complex magnetic polarities. Groups of this type are generally considered most likely to cause storms. By September 17, the spot‐group had attained an area of 2000 millionths of the Sun's visible hemisphere which places it among the largest of the present cycle, a group of area 1000 being considered “large.” Since the date was near the autumnal equinox the latitude of the center of the disk was at its maximum value of 7° north. The spot‐group thus crossed the meridian about 5° north of the central point. When the storm began the spot‐group extended from 10° to 25° of longitude (or from about 0.8 to 1.9 days) west of the central meridian.
Sitka Magnetic Observatory, July to September, 1941
Authors: Gebhardt Robert E.
Published: February 2008

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

July 4–5—A major magnetic storm began suddenly at 03h 52m GMT, July 4, with a sharp motion of all traces. Conditions remained comparatively calm with gradually increasing storminess until 06h, July 5. Until 16h, July 5, the trace was very disturbed and could be identified in only a few places. The K‐values during the storm were 9 for three three‐hour intervals. After 17h, July 5, there was a gradual return to normal.
Cheltenham Magnetic Observatory, July to September, 1941
Authors: Ludy Albert K.
Published: February 2008

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

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

(Latitude 18° 38′.3 N., longitude 72° 52′.3 or 4h 51m.5 E. of Gr.)

April 24—A magnetic storm of moderate intensity commenced gradually at 07h 00m GMT, April 24. H was maximum at 07h 37m and began to fall afterwards and reached the minimum value at 16h 26m. The storm ended at about 22h. Ranges: D, 7′.7; H, 209 gammas; Z, 40 gammas.
Watheroo Magnetic Observatory, July to September, 1941
Authors: Parkinson W. C.
Published: February 2008

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

July 4–7—This disturbance of unusual severity began at 03h 42m GMT, July 4, with sudden small movements followed by irregular, but relatively small, fluctuations in the traces. These conditions lasted until 04h 59m, July 5, when sudden impulses were recorded in all three elements and the traces immediately became violently disturbed,, remaining so until 16h. During this period H decreased to a value of 530 gammas below normal. The greatest sudden change in the interval was between 14h 07m and 14h 33m when H increased 285 gammas. Between 14h 23m and 14h 33m westerly declination decreased by 63′, which was practically the total range in declination during the whole disturbance. Z increased to such values between 08h and 15h that they were beyond the limits of registrations for the greater portion of the time. Although the violence of the disturbance had abated by 16h, July 5, and H had gradually regained its normal value, the traces continued to be moderately disturbed as follows: 20h to 22h on July 5; 13h to 16h on July 6; 00h to 05h on July 7. The disturbance ceased at 21h, July 7. Ranges: D, 65′2; H, 563 gammas; Z, greater than 215 gammas (probably more than 500 gammas). A brilliant display of the Aurora Australis was visible at the Observatory during the evening of July 5. At 10h 30m GMT, or 18h 30m 120° MT (E. of Gr.), an hour after sunset, a bright glow was seen on the southern horizon; it gradually became more pronounced and by 11h 50m had developed into an arch spreading from south‐southeast to south‐southwest and about 35° above the horizon at its highest part. At 12h 10m the arch was at its brightest and was tinged with red. at its eastern and western extremities. Brilliance then diminished slightly and by 12h 30m had almost disappeared, although the general glow still persisted. Between 14h and 14h 30m the glow, still visible, was varied by the appearance of luminous vertical shafts changing rapidly in range, intensity, and position. This display continued until after 14h 40m after which time only the glow was observed and this gradually faded. The whole display would have been even more imposing but for the presence of the Moon which was nearing the full.
Alibag Magnetic Observatory October to December, 1941
Authors: Rangaswami M. R.
Published: February 2008

October 11‐12—A disturbance of moderate intensity commenced gradually at about 06h GMT, October 11. H reached its maximum value at 07h 52m and thereafter began to fall. The minimum in H was attained at 13h 17m, October 11. The disturbance practically ended at about 03h, October 12. Ranges: D, 4′.7; H, 142 gammas; Z, 26 gammas.
Further note on the effect on cosmic‐ray intensity of the magnetic storm of March 1, 1942
Authors: Lange Isabelle , Forbush Scott E.
Published: February 2008

In a previous note [Terr. Mag., 47, 185–186 (1942)], the authors called attention to the considerable decrease in cosmic‐ray intensity at Cheltenham (Maryland) and Huancayo (Peru) observed during the magnetic storm of March 1, 1942. In Figure 1 of that note two bihourly mean values, one on February 28 and the other on March 7, for Cheltenham, were nearly seven per cent above the pre‐storm average. Such an apparent sudden large increase in intensity had not been observed before and the values were therefore questioned. The first of these values was corroborated, however, by independent observations at Norfolk (Virginia) [E. B. Berry and V. F. Hess, Terr. Mag., 47, 251‐256 (1942)].
Tucson Magnetic Observatory July to September, 1942
Authors: Nelson J. H.
Published: February 2008

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

July 10–12—A storm of moderate intensity began at 23h 35m GMT, July 10, with a sudden increase in H of about 25 gammas. The first fourteen hours of the storm consisted principally of irregular long‐period variations of D and H, with, as usual for this station, little disturbance of Z. The activity during the last half of the storm was less intense, and it ended about 12h, July 12. Ranges: H, 123 gammas; D, 16′; Z, 40 gammas.
Archaeologica geomagnetica
Authors: Chapman Sydney
Published: February 2008

Today the well‐being of the average citizen is linked with social and economic events widespread over the world. The future of human life will depend more and more on the education, the intelligence, and the knowledge of the common man. Knowledge increases continually in range and complexity, and the days in which a man might master almost the whole of human learning lie far behind us. The citizen should have a rational though of course simple conception of the world as it is today, and of the past history of man and the world; how to achieve this is one of the great problems of education.
Solar and magnetic data, October to December, 1942, Mount Wilson Observatory
Authors: Nicholson Seth B. , Mulders Elizabeth Sternberg
Published: February 2008

A small magnetic disturbance occurred on October 2–3. Only very small sunspots were visible.

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

Part II, Chapter 8—On the northeasting1 of the needles

The northeasting of the needles causes navigators many doubts, from which they may be freed by knowing precisely how much the needles northeast or northwest. In addition to this, other advantages will follow, such as knowing exactly in what direction they are sailing. Knowing this they will follow exactly their courses without error or wandering, and also it will help much to a knowledge of the longitude in which they are navigating.
THREE‐HOUR‐RANGE INDEX, K, AT DOMBÅS OBSERVATORY DURING 1939 TO 1942
Authors: Wasserfall K. F.
Published: February 2008

Introduction—The following resolution was adopted [see 1 and 5 of “References” at end of paper] by the Washington Meeting of the International Association of Terrestrial Magnetism and Electricity in September 1939: “That cooperation of magnetic observatories be sought for a three‐year period (1940‐42) in an international trial‐scheme for provision of three‐hour‐range index K, to characterize the variation in degree of irregular magnetic activity throughout each day, especially in order to meet the request made by the International Union of Scientific Radio‐telegraphy and other bodies for information concerning the magnetic activity more detailed than the present daily magnetic character‐figure, and that this trial‐scheme should replace the scheme for a numerical character‐figure.”

The so‐called “Potsdamer erdmagnetische Kenziffer,” which was introduced for Potsdam at the beginning of 1938 [2], served as a model for the index K. Bartels, Heck, and Johnston [3] have given a definition of K; here it will suffice to say that this definition agrees more or less with that for the quantity “storminess” (5) as defined by Krogness and Wasserfall [4]. For S, as well as for K, the range is the difference between the curve actually registered and an arbitrary curve showing quiet conditions. The curve for quiet conditions includes, for “absolute storminess” (AS), the mean daily and day‐to‐day quiet variations, Q and C, respectively, and for K the combined effect of Sq, L, and Dma, where Sq is the solar daily variation, L the lunar daily variation, and Dma the after‐effect of the disturbing‐field (the effect of the decay of the ring‐current), and the non‐cyclic variation on quiet as well as that on the disturbed days [3].
SOLAR AND MAGNETIC DATA, APRIL TO JUNE, 1943, MOUNT WILSON OBSERVATORY
Authors: Nicholson Seth B. , Mulders Elizabeth Sternberg
Published: February 2008

No magnetic storms were recorded in the second quarter of 1943, although active sunspot‐groups (Mount Wilson Nos. 7571, 7573, 7578, and 7579) with bright chromospheric eruptions were present.

Although sunspot‐groups of the new cycle have appeared, minimum sunspot‐activity will probably not be reached for some months. The high‐latitude groups Nos. 7579 and 7582 were certainly members of the new cycle.1 Group 7532, which crossed the central meridian on December

1Pub. Astr. Soc. Pacific, 55, 182 (1943).

20, 1942, probably belonged to the new cycle, although its polarities were like those of the waning cycle.2

2Pub. Astr. Soc. Pacific, 55, 43 (1943).
TUCSON MAGNETIC OBSERVATORY APRIL TO JUNE, 1943
Authors: Nelson J. H.
Published: February 2008

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

April 2‐4—A moderate storm began suddenly at 23h10m GMT, April 2, with an increase of 23 gammas in Hduring the first five minutes. There was little outstanding activity and conditions were relatively quiet again by about 08h, April 4. Ranges: D, 11′; H, 80 gammas.
APIA MAGNETIC OBSERVATORY APRIL TO JUNE, 1943
Authors: Sapsford H. Bruce
Published: February 2008

(Latitude 13° 48′.4 S., longitude 171° 46′.5 or 11h 27m.l W. of Gr.)

There were no magnetic disturbances of any importance during the quarter.
MAGNETIC OBSERVATORY, HERMANUS APRIL TO JUNE, 1943
Authors: Ogg A.
Published: February 2008

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

April 2‐7—Disturbances began without conspicuous abruptness (H increased 14 gammas in ten minutes) at 21h 05m GMT, April 2. The disturbances continued until 21h, April 7. The largest K‐index value was 5 in the period 00h‐03h, April 3.
MEAN K‐INDICES FROM TWENTY‐ONE MAGNETIC OBSERVATORIES AND FIVE QUIET AND FIVE DISTURBED DAYS FOR 1942
Authors: Johnston H. F.
Published: February 2008

To date K‐indices have been received at the Department of Terrestrial Magnetism from 21 magnetic observatories for the year 1942. Those contributing were, in order of geomagnetic latitude: College; Sodankylä; Lerwick; Dombâs; Meanook; Sitka; Esktlalemuir; Rude Skov; Agincourt; Witteveen; Abinger; Cheltenham; San Fernando; Tucson; San Juan; Honolulu; Huancayo; Hermanus; Watheroo; Too‐langi; and Amberley. College, Sodankylä, Toolangi, and Amberley were not included in the list of contributing observatories published [see 1 of “References” at end of paper] in the June 1941 issue of this JOURNAL. The lower limit for a K‐index of 9 is 2500γ at College, 1500γ at Sodankylä, 35γ7 at Toolangi, and 500γ at Amberley.
PREDICTIONS FOR THE COMING SUNSPOT‐CYCLE
Authors: Gleissberg W.
Published: February 2008

In view of the close relations between terrestrial magnetism and solar phenomena readers of the JOURNAL will be interested in the fact that during recent years some progress has been made on the problem of sunspot‐predictions. Methods for predicting sunspot‐numbers have been developed by Waldmeier [see 1 of “Reference” at end of paper], by Stewart and his collaborators [2, 3], and by the present writer [4, 5]. While the methods of Waldmeier and of Stewart permit us only to predict the remaining course of the current spot‐cycle from its initial course [6, 7], my method enables us to predict the behavior of the coming spot‐cycle. Moreover, the probability of the predictions made by my method can be computed from the probability‐laws of sunspot‐variations [8].
Huancayo Magnetic Observatory, October to December, 1943
Authors: Ledig Paul G.
Published: February 2008

Latitude 12° 02′.7 S., longitude 76° 20′.4 or 5h 01m.4 W. of Gr.]

November 19–27— Beginning gradually in the early hours of November 19, a magnetic disturbance was recorded which continued at approximately the same intensity for about nine days. The maximum range in horizontal intensity occurred on November 19 and was 225 gammas. The disturbance during the entire period was characterized by small but relatively rapid changes in H and by an almost complete absence of the usual large increase during the daylight hours. There was also a moderate decrease in the mean H‐values during the period and slight disturbance in D and Z.
Atmospheric‐Electric Observatories at Huancayo, Peru, during the Solar Eclipse, January 25, 1944
Authors: Jones M. W. , Giesecke A. A.
Published: February 2008

Introduction

During the solar eclipse of January 25, 1944, (08h 04m to 10h 44m) which reached 88 per cent totality at Huancayo, Peru, at 09h 18m, it seemed desirable that the Huancayo Magnetic Observatory (latitude 12° 02′.7 south, longitude 75° 20′.4 west, altitude 3300 meters) of the Department of Terrestrial Magnetism of the Carnegie Institution of Washington, make special observations of several components of the geophysical program of the Observatory. These included observations of the potential‐gradient of the atmosphere, positive and negative conductivity, and nuclei‐count. A description of the method for measurement of the potential‐gradient and the conductivity can be found elsewhere [see 1 of “References” at end of paper]. Jones and Ledig [2] have shown that in the early morning hours at Huancayo there is a variation in potential‐gradient and conductivity which may be attributed to heating effects of the Sun. It appeared that during a solar eclipse interesting data would be obtained due to the variation in heating effect on the lower strata of the atmosphere. An increase in heating decreases the stability of this lower stratum and causes a mixing of this layer with higher strata, gradually bringing in more nuclei and consequently decreasing the conductivity of the air. The reverse would be expected during a solar eclipse.