bluuebunny/crossref_metadata_2025 huggingface dataset:
Further evidence of a latitude‐effect in potential‐gradient
Authors: Gish O. H.
Published: February 2008

That potential‐gradient is less in low than in high latitudes was determined by Mauchly from data obtained on Cruises IV, V, and VI of the Carnegie. The evidence for this effect is better than was suspected by Mauchly, who based his comparison on the overall mean values of all cruises for various latitude‐belts. In this comparison the considerable variation from cruise to cruise and from season to season in the mean gradient tends to confuse the evidence, but if for each group of data, according to season, latitude, and cruise, a ratio is formed of the value in a given latitude‐belt to that in the central latitude‐belt, the confusion of evidence introduced by the temporal changes in gradient is reduced. The weighted mean values for the ratios, thus obtained, are plotted against the mean latitude of the respective belts in Figure 1.
Sudden‐commencement magnetic storms in 1941
Authors: Ogg A.
Published: February 2008

As a comparison of the sudden‐commencement storms reported in the JOURNAL proved of interest, the times of commencement were assembled as in Table 1. The times are Greenwich mean time. Only storms, which are stated in the reports to be sudden‐commencement storms, are quoted.

At Hermanus Observatory the time is recorded on the magnetograms by a very accurate Synchronome slave clock.
Effect of smoke on the atmospheric‐electric elements at the Watheroo Magnetic Observatory
Authors: Wait G. R.
Published: February 2008

Intense smoke at the Watheroo Magnetic Observatory effectively increases the total resistance of the vertical column of air over the station. This and other evidence indicate that the smoke extends to a height of about one km. The total resistance of the vertical column of air over the Observatory varies greatly through the day. Both the variation and the average value are increased by the presence of smoke. Factors other than the number of condensation‐nuclei and radioactive matter in the atmosphere, it is believed, may be effective in producing a diurnal variation in this total resistance. The intensity of smoke at Watheroo appears to be independent of the direction and velocity of the wind. The rate of ionization (small‐ion production) in the lower atmosphere over a station on land is found to vary considerably through the day, being greatest during the early morning hours and least during the evening. The cause for the variation appears to be a variation in the amount of radioactive matter in the air.
Solar and Magnetic Data, January to March, 1943, Mount Wilson Observatory
Authors: Nicholson Seth B. , Mulders Elizabeth Sternberg
Published: February 2008

No magnetic storms were recorded in the first quarter of the year 1943. Two magnetic disturbances occurred, however, in which the horizontal component decreased by more than 100 gammas. The first began at about 19h GMT, January 20, the second about 16h GMT, March 29.

Three large sunspot‐groups were observed: Mount Wilson No. 7550, which crossed the central meridian on February 11.7; No. 7555, on February 25.7; and No. 7559, on March 10.6. These groups, although large, were only moderately active; they were not accompanied by significant geomagnetic activity.
Tucson Magnetic Observatory, January to March, 1943
Authors: Nelson J. H.
Published: February 2008

(Latitude 32° 14′.8 N., longitude 110° 50′.1 or 7h 23m.4 W. of Gr.)

January 4–5—A very mild storm began about 10h GMT, January 4, and continued for approximately twenty‐four hours. The principal characteristic seemed to be irregular oscillations of moderately short period of D and H. Ranges: D, 11′; H, 76 gammas.
Apia Magnetic Observatory, January to March, 1943
Authors: Sapsford H. Bruce
Published: February 2008

(Latitude 13° 48′.4 S., longitude 171° 46′.5 or 11h 27m.1 W. of Gr.)

January 4–5—At 10h GMT, January 4, an emergent disturbance commenced and lasted until 17h. The trace remained slightly disturbed until 10h, January 5.
REMARKABLE AURORAL FORMS, MEANOOK OBSERVATORY, POLAR YEAR, 1932–33
Authors: Vestine E. H.
Published: February 2008

Störmer1 has discussed various remarkable auroral forms noted in Southern Norway during the course of many years of auroral observations. Among these were several examples of long, feeble homogeneous arcs, of uniform narrow and sharply‐defined width, noted at heights about 200 km above the Earth—nearly twice the height of the usual homogeneous arcs. An arc of this kind was noted by Störmer on February 22, 1911. On September 29, 1930, a similar arc was noted with an average measured height of lower border of 195 km, and of upper border 232 km.
SITKA MAGNETIC OBSERVATORY JULY TO SEPTEMBER, 1943
Authors: Pinckney Harold W.
Published: February 2008

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

July 3—Gradually increasing deviations from normal preceded by half a day a briefly severe disturbance occurring between 04h and 09h GMT, July 3, during which was recorded a range of 730 gammas in H.
American Magnetic Character‐Figure, CA Three‐Hour‐Range Indices, K, and Mean K‐Indices, KA, for October to December, 1943, and Summary for Year 1943
Authors: Johnston H. F.
Published: February 2008

Summaries of American URSI broadcasts have appeared regularly in this JOURNAL since the issue for December, 1930.

As set forth in this JOURNAL for June, 1937, “The Department of Terrestrial Magnetism and the United States Coast and Geodetic Survey with the cooperation of the United States Army and the United States Navy communication‐services and several amateur radio stations have undertaken to supply the American character‐figure based upon the reports of the seven American‐operated observatories—those of the Department of Terrestrial Magnetism at Huancayo in Peru and at Watheroo in Western Australia, and those of the United States Coast and Geodetic Survey at Cheltenham (Maryland), Honolulu (Hawaii), San Juan (Puerto Rico), Sitka (Alaska), and Tucson (Arizona).” This character‐figure is being designated CA, and its values for the first twelve, the second twelve, and all twenty‐four hours of each Greenwich day for October to December, 1943, are given in Table 1.
Preliminary Magnetic Character‐Figures, C, for 1942 and Lists of Five Selected Quiet and Disturbed Days for January to June, 1943
Authors: Johnston H. F.
Published: February 2008

Reports of magnetic character on a scale of 0, 1, and 2 have now been received from a total of 43 observatories for the year 1942. The preliminary International Character‐Figures, C, for 1942 are given in Table 1. These figures will closely approximate the final values that can be derived when characters are available from more magnetic observatories.

Reports of geomagnetic activity for the first six months of 1943 have been received from a sufficient number of observatories so that the international quiet and disturbed days can be selected in accordance with the method outlined on pages 219–227 in the December 1943 issue of this JOURNAL. The selected days are shown in Table 2. The selection is based on the reports of magnetic character on a scale of 0, 1, 2 from 40 observatories and on the reports of K‐indices from 23 observatories.
The Geographic Incidence of Aurora and Magnetic Disturbance, Northern Hemisphere
Authors: Vestine E. H.
Published: February 2008

Fritz [see 7 of “References” at end of paper] in a famous memoir published in 1881 discussed the frequency and characteristics of aurora observed in the Northern Hemisphere during the years 1700 to 1872. Using observations during this 172‐year period [8] he also constructed his well‐known map of isochasms of equal auroral frequency.

Beginning is made here in the statistical analysis of the auroral data since accumulated, a task of considerable magnitude if undertaken with any pretense at completeness. The present paper is concerned mainly with the variation with geographic position of the average daily frequency of aurora in high latitudes, and of geomagnetic disturbance.
American Magnetic Character‐Figure, CA, Three‐Hour‐Range Indices, K, and Mean K‐Indices, KA, for January to March, 1944
Authors: Johnston H. F.
Published: February 2008

Summaries of American URSI broadcasts have appeared regularly in this JOURNAL since the issue for December, 1930.

As set forth in this JOURNAL for June, 1937, “The Department of Terrestrial Magnetism and the United States Coast and Geodetic Survey with the cooperation of the United States Army and the United States Navy communication‐services and several amateur radio stations have undertaken to supply the American character‐figure based upon the reports of the seven American‐operated observatories—those of the Department of Terrestrial Magnetism at Huancayo in Peru and at Watheroo in Western Australia, and those of the United States Goast and Geodetic Survey at Cheltenham (Maryland), Honolulu (Hawaii), San Juan (Puerto Rico), Sitka (Alaska), and Tucson (Arizona).” The H‐variometer at Honolulu was not in operation during the period from March 12 to March 31. This character‐figure is being designated CA, and its values for the first twelve, the second twelve, and all twenty‐four hours of each Greenwich day for January to March 1944, are given in Table 1.
Apia Observatory, January to March, 1944
Authors: Sapsford H. Bruce
Published: February 2008

(Latitude 13° 48′.4 S., longitude 171° 46′.5 or 11h 27.1m W. of Gr.)

February 13–14—H became disturbed at 23h 00m GMT, February 13. A maximum was reached at 00h 19m, February 14, and decreased steadily to a minimum at 07h 05m. After this the intensity increased with fluctuations to 14h 06m, when the trace became normal. D and Z were slightly disturbed. Range in H was 155 gammas.
Cheltenham Magnetic Observatory, July to September, 1944
Authors: Hershberger John
Published: February 2008

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

August 2–3—A rather severe storm began, after some hours of minor activity, at about 21h GMT, August 2, and ended at about 12h, August 3. Throughout the storm, the longer‐period fluctuations predominated. The greatest activity occurred in declination, the total range of which was just over 1°. K‐indices of 7 were recorded for the first two three‐hour periods of August 3, and indices of 6 for the next two periods.
Watheroo Magnetic Observatory, July to September, 1944
Authors: Parkinson W. C.
Published: February 2008

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

September 30—Between 13h and 16h GMT, September 30, there was a large bay and peak shown in all three elements. The first feature was most clearly shown in the H‐trace and H reached its minimum value at 14h 47m. Thereafter H quickly increased until it reached its maximum value at 15h 05m. A corresponding bay in the Z‐trace culminated at the same time, while the westerly declination reached a minimum value at 15h 04m. Ranges: D, 11′.2; H, 77 gammas; Z, 88 gammas.
Cheltenham Magnetic Observatory, October to December, 1944
Authors: Hershberger John
Published: February 2008

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

October 10–11—A period of moderate activity beginning at about 19h 20m GMT, October 10, and ending at about 06h, October 11, included a rather deep bay in declination which resulted in a K‐index of 6 for the second three‐hour period of October 11.
Tucson Magnetic Observatory, October to December, 1944
Authors: Nelson J. H.
Published: February 2008

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

October 10–11—A moderate storm began about 19h GMT, October 10, without sharp beginning. A prominent but irregular bay in H occurred between 00h and 06h, October 11, during which period D reached its eastward maximum. Following this there was only mild activity until a 3‐hour period beginning at 14h, during which moderate variations in D and H occurred; then there was again only mild disturbance until the end of the storm about 24h, October 11. Ranges: D, 15′.5; H, 123 gammas; Z, 36 gammas.
Huancayo Magnetic Observatory, October to December, 1944
Authors: Ledig Paul G.
Published: February 2008

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

October 11—There was a short magnetic disturbance which began gradually at about 13h GMT, October 11, and was characterized by a rapid decrease in H between 15h 40m and 15h 50m, and with a very large decrease from 16h 10m to 16h 35m and a very low minimum at 16h 48m. The range was 295 gammas in a little over an hour. The disturbance died out rapidly after 17h and affected D and Z only mildly.
The Comparison of Horizontal‐Intensity Magnetometers
Authors: Ogg A.
Published: February 2008

A paper on “The determination of the horizontal component of the Earth's magnetic force at the Magnetic Observatory, Hermanus” by A. Ogg, B. Gotsman, and A. M. van Wijk [see 1 of “References” at end of paper], which dealt mainly with the theory of the Adolf Schmidt standard magnetometer and a simplified method of using it, contained results of the comparison of different types of horizontal‐intensity magnetometers. Since these results were published further data are available for this comparison.

The magnetometers, which were available for this comparison, were the three la Cour horizontal‐force magnetometers (QHM) 29, 30, and 58; CIW magnetometer 17; the Adolf Schmidt standard magnetometer; and the F. E. Smith coil‐magnetometer.
Results of the Magnetic Observatory, University of Cape Town, 1937–40
Authors: Scott W. E.
Published: February 2008

For obvious reasons, publications of magnetic results by observatories during the present war‐period have been few and far between. Under the circumstances, it is felt that gratification should be expressed and attention directed to the printed results just received (years 1937–40) from the Magnetic Observatory, University of Cape Town, under the able direction of Dr. A. Ogg. This publication is noteworthy for its comprehensiveness arid conciseness, despite the great difficulties of present day. It will be recalled that Cape Town was one of the network of stations of the Second International Polar Year, 1932–33.
Solar and Magnetic Data, January to March, 1945, Mount Wilson Observatory
Authors: Nicholson Seth B. , Mulders Elizabeth Sternberg
Published: February 2008

During the magnetic storm of January 15 no significant solar activity was observed. At the beginning of the storm of January 28, an active bipolar sunspot‐group of the old cycle, Mount Wilson No. 7719, latitude 7° south, which developed on the disk sometime between January 24 and 27, was 37° west of the central meridian.

When the storm of March 11 began, a large group, No. 7729, latitude 14° south, was 2.1 days past the central meridian. A solar flare was observed near this group on March 10 from 16h 51m to 18h 43m GCT. When the storm of March 14 began, the group was near the west limb. Clouds prevented observations on March 13, 14, and 15.
Not on Magnetic Character‐Figures C for 1943
Authors: Swoboda G.
Published: February 2008

Herewith (Table 1) are the daily international magnetic character‐figures C for 1943, established by Professor J. Bartels and essentially derived from the data of 16 observatories.

Professor Bartels also selected as days of magnetic disturbance during 1943 for reproduction the following (hours given are in universal time, that is, GMT):
Tucson Magnetic Observatory July to September, 1945
Authors: Westerman C. Edward
Published: February 2008

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

August 27–29—A moderate magnetic storm began at 20h GMT on August 27, with H gradually increasing for the first five hours while D remained more or less normal. During the next three hours, 01h‐4h on August 28, H plunged approximately 190 gammas while D fluctuated within a range of only 8′. H recovered partially for the next two hours and then gradually drifted back to normal while D remained fairly undisturbed until the end of the storm at 07h on August 29. Z was undisturbed throughout except for a slight gradual increase during which time H dropped 190 gammas.
Huancayo Magnetic Observatory July to September, 1945
Authors: Ledig Paul G.
Published: February 2008

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

August 28—Although there were no real disturbances during August, there was an unusual, deep bay recorded in H on August 28. This occurred between 01h and 05h GMT and consisted entirely of a large and slow decrease to a point 153 gammas below the H base‐line and then a return to practically the normal position of the H‐trace. There was no disturbance following this bay, nor any marked changes in D or Z.
Watheroo Magnetic Observatory July to September, 1945
Authors: Parkinson W. C.
Published: February 2008

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

There were no major magnetic disturbances during July to September, 1945.
Three‐hour‐range indices, K, of geomagnetic activity at the magnetic observatory, Hermanus, comparison with K‐indices at American‐operated observatories, and mean K‐indices, KA, for the years 1941–44
Authors: Ogg A.
Published: February 2008

At the Washington Meeting of the International Association of Terrestrial Magnetism and Atmospheric Electricity in September, 1939, it was decided to adopt a new international measure of magnetic activity to meet requests for more detailed information than the daily magnetic‐character figure. It was decided to invite the cooperation of magnetic observatories in a three‐year period (1940–42) trial‐scheme of a three‐hour‐range index to replace the numerical‐character figure.

The so‐called “Potsdamer erdmagnetische Kennziffer,” which was introduced for Potsdam in 1938 served as a model for what is called the index K. To start this trial‐scheme an important paper on the definition of K and on the fixing of K‐scales for the various observatories taking part in the scheme was published in this Journal [44, 411–454 (1939)] and also by the same authors a paper on the main features of daily magnetic activity at the observatories Sitka (Si), Cheltenham (Ch), Tucson (Tu), San Juan (SJ), Honolulu (Ho), Huancayo (Hu)7 and Watheroo (Wa) for the years 1938–39 [Terr. Mag., 45, 309–337 (1940)].
Atmospheric‐electric potential‐gradient in Kokkola, Finland, during the solar eclipse of July 9, 1945
Authors: Sucksdorff E.
Published: February 2008

In addition to other geophysical and geodetical investigations made in Finland in connection with the total solar eclipse in the summer of 1945, a set of measurements was also made of the atmospheric‐electric potential‐gradient. The latter was to determine the influence of the eclipse on changes in the potential‐gradient for comparison with the variations on the following days. The observations were made in the neighborhood of the small town of Kokkola in the north of Finland (latitude = 63° 51′ north, longitude = 23° 10′ east). A small field about two km northeast of the town was selected as place of observation. Its situation is 2.5 km from the Gulf of Bothnia at an elevation above sea‐level of only a few meters, and 11 km southwest from the central line of the eclipse.
Geomagnetic storm at Elisabethville, March 28, 1946
Authors: Scott W. E.
Published: February 2008

Dr. G. Heinrichs, Director of the Elisabethville Magnetic Observatory, Elisabethville, Katanga, Belgian Congo, reported the geomagnetic storm of March 28–29, 1946, as one of the “strongest” storms ever recorded there, approximating in severity and range that of March 1, 1941.

Figure 1 shows the record of the magnetic storm at the Elisabethville Magnetic Observatory. The beginning of the storm—between 06h and 07h—was lost because the reserve recording‐spot was being adjusted at the time. Detailed accounts of the associated geomagnetic disturbance at individual observatories appear elsewhere in this issue of the Journal. However, several aspects merit some comment.
Five international quiet and disturbed days for July to September, 1945
Authors: Scott W. E.
Published: February 2008

Reports of geomagnetic activity for the third quarter of 1945 have been received from a sufficient number of observatories so that the international quiet and disturbed days can be selected in accordance with the method outlined on pages 219–227 in the December, 1943, issue of this Journal. The selection is based on the reports of magnetic character on a scale of 0, 1, and 2 from 32 observatories and of K‐indices from 28 observatories.
On diffusion in the ionosphere
Authors: Ferraro V. C. A.
Published: February 2008

It is shown that Jaeger's discussion of diffusion in the ionosphere is applicable only to regions of the F2‐layer 100 km or more above the level of maximum ion‐production. Further reasons are given for the conclusion reached in an earlier paper that, though diffusion in the F2‐layer may not be negligible (as in the case of the E‐ and F1‐regions), its effect is likely to be small. The air‐density in the F2‐layer at the level of maximum electron‐density is then unlikely to be much less than 1010 mol per cc.
Preliminary results, auroral photographs, southern Norway, March 1946
Authors: Störmer Carl
Published: February 2008

Table 1 summarizes number of successful exposures for photographs of auroras in southern Norway at a single station (I), simultaneous sets at 2, 3, 4, and 5 stations (II, III, IV, V), sets usable for determinations of height, total (Σ), and stations in action.
Five International quiet and disturbed days for January to March, 1946
Authors: Scott W. E.
Published: February 2008

Reports of geomagnetic activity for the first quarter of 1946 have been received from a sufficient number of observatories so that the International quiet and disturbed days can be selected in accordance with the method outlined on pages 219–227 in the December, 1943, issue of this Journal. The selection is based on the reports of magnetic character on a scale of 0, 1, and 2 from 35 observatories and of K‐indices from 28 observatories.
Cheltenham Magnetic Observatory July to September, 1946
Authors: Wiles William E.
Published: February 2008

(Latitude 38° 44′.0 N., longitude 76° 50′.5 or 5h 07m3 W. of Gr.)

July 18–19—Following a very slight disturbance in D and H, a mild magnetic storm began with a sudden commencement in all three elements at 09h 04m GMT, July 18, and persisted until about 15h, July 19. The first half of the storm consisted of rapid pulsations of small amplitude in both H and D. The character of the disturbance gradually changed to irregular oscillations of moderate amplitude, the change occurring in D at about 22h, July 18, and in H at about 02h, July 19. The Z‐trace did not exhibit serious disturbance at any time. Two K‐indices of 5 and six of 4 were recorded.
Tucson Magnetic Observatory July to September, 1946
Authors: Westerman C. Edward
Published: February 2008

(Latitude 32° 14′.8 N., longitude 110° 50′.1 or 7h 23m3 W. of Gr.)

July 7–8—A moderate storm of only about twenty‐four hours' duration began at 03h GMT, July 7. Most of the activity occurred during the first half of the period and was characterized by moderate, fairly long‐period changes in H. Little activity was noted in D and Z. Range in H: 163 gammas.
American magnetic character‐figure, CA, three‐hour‐range indices, K, and mean K‐indices, KA, for October to December, 1946, and summary for year 1946
Authors: Scott W. E.
Published: February 2008

Summaries of American URSI broadcasts have appeared regularly in this Journal since the issue for December, 1930.

As set forth in this Journal for June, 1937, “The Department of Terrestrial Magnetism and the United States Coast and Geodetic Survey with the cooperation of the United States Army and the United States Navy communication‐services and several amateur radio stations have undertaken to supply the American character‐figure based upon the reports of the seven American‐operated observatories—those of the Department of Terrestrial Magnetism at Huancayo in Peru and at Watheroo in Western Australia, and those of the United States Coast and Geodetic Survey at Cheltenham (Maryland), Honolulu (Hawaii), San Juan (Puerto Rico), Sitka (Alaska), and Tucson (Arizona).“ This character‐figure is being designated CA, and its values for the first twelve, the second twelve, and all twenty‐four hours of each Greenwich day for October to December, 1946, are given in Table 1.
Mean K‐indices from thirty magnetic observatories and preliminary international character‐figures, C, for 1945
Authors: Scott W. E.
Published: February 2008

K‐indices have been received at the Department of Terrestrial Magnetism from 32 magnetic observatories for the year 1945. The records are not complete from all, but the average number reporting was 30. Those contributing were in order of geomagnetic latitude: Godhavn; Ivigtut (through July 16, 1945); College; Lerwick; Dombås; Meanook; Sitka; Eskdalemuir; Rude Skov; Agincourt; Witteveen; Abinger; Srednikan; Yakutsk; Cheltenham; Zaimishche; Vyssokaya Dubrava; Moscow; Zuy; San Fernando; Tucson; Dusheti; Tashkent (Keles); San Juan; Honolulu; Huancayo; Apia; Filar; Hermanus; Watheroo; Toolangi; and Amberley. [During 1946 the Alibag Magnetic Observatory, under the direction of Dr. S. K. Chakrabarty, initiated the three‐hour‐range indices, K.]
Geophysical work of the National Geological Survey of China and of the Institute of Physics of the National Academy of Peiping of China
Authors: Wong Wen‐Hao
Published: February 2008

(I) Academic research

(A) Seismological observation—The Chiufeng Seismological Observatory was founded in 1929. It had a complete set of Wiechert seismographs for recording earthquakes of east Asia, and a complete set of the newest type of Galitzin seismographs for recording the remotest quakes. Observation work was headed by Dr. S. P. Lee since the very beginning. A monthly bulletin was published which provided valuable data for many foreign seismological stations. During 1929 to 1937 more than 2300 earthquakes were recorded, 500 of which can be used for the study of subcrustal conditions of the Earth. When Peiping fell to the Japanese in the summer of 1937, the Observatory was lost and observational work suspended.
Alibag Magnetic Observatory October to December, 1946
Authors: Rao M. P.
Published: February 2008

(Latitude 18° 38′ N., longitude 72° 58′ E. or 4h 51m.5 E. of Gr.)

November 5–6—A moderate disturbance commenced suddenly at 09h 22m, GMT, November 5, and continued till about 17h 30m, November 6. All the three elements recorded moderate fluctuations. The highest K‐index attained during the period was 5.
A nomograph for conversion of Fourier coefficients occurring in geomagnetic computations
Authors: Schneider Otto
Published: February 2008

Whenever a numerical operation of standard type is to be repeated a great number of times, as often occurs with geomagnetic material of statistical character, the use of nomographs may prove convenient, since it represents a considerable saving of time, provided that the amount of work is large enough to compensate the time of preparing and drawing the nomograph. In the present note, attention is drawn to the practical advantages of this method, widely used in other branches of geophysics and in engineering.

A very simple example is given by the following case, referring to an analysis of S and L at Batavia. In the course of that investigation, a great number of pairs of harmonic coefficients representing diurnal and semidiurnal variations on individual days had to be transformed in amplitude and phase due to a change, in 1920, of the tabulating scheme adopted by that observatory. Starting with January 1, 1920, hourly mean values according to standard time (105° meridian) were published instead of instantaneous values for local mean time. Therefore, the harmonic coefficients for days after January 1, 1920, must be reduced in the following way:
Meeting of Committees Annales de Géophysique, November 8, 1946
Authors: Coulomb J.
Published: February 2008

The Patronage and Editing Committees of the Annales de Géophysique met November 8, 1946. There were present: MM. Barrabe; Cabannes; Cagniard; Chalonge; Coulomb; Goguel; Jouaust; Labrouste; Lanquine; R. P. Lejay; Tardi; Thellier; and Vassy. Excused were: MM. Bureau; Lacroix; Le Grand; Migaux; Rothé; and Vignal. Decisions adopted were as follows.
Some early signal‐intensity measurements
Authors: Seaton S. L.
Published: February 2008

Eighteen years ago the Department of Terrestrial Magnetism of the Carnegie Institution of Washington, collected radio wave‐propagation data throughout the world during Cruise VII of the research Yacht Carnegie. In 1930 the log‐books of the yacht were examined for high‐frequency radio‐propagation data which were abstracted and summarized.

One of the studies undertaken by means of these data was a collection of radio signal‐strengths over long distances in terms of local time at the midpoint of the path of propagation. The reasoning which led to the reference‐time of this path's midpoint was prompted by the fact that the signal‐strength data were collected on a moving observatory. Since the yacht cruised in all oceans and made measurements of signals arriving from all directions, it appeared natural to choose a time‐scale upon which it was possible to represent the information in such a way that any portion of it could be compared with any other part. There resulted a graph of Figure 1.
Eclipse expedition to study ionosphere
Authors: Grosvenor Gilbert
Published: February 2008

What happens to the nebulous ionosphere, the all‐important radio‐reflecting layer high above the Earth, when the Moon's shadow “punches a hole” in it during an eclipse of the Sun? This will be investigated on May 20, 1947, by the Army Air Forces‐National Geographic Society Eclipse Expedition at Bocayuva, Brazil. Because the ionosphere is created by ultraviolet radiation from the Sun, which makes air‐molecules in the upper atmosphere electrically conducting, scientists are interested in knowing what happens to the ionosphere when this radiation is cut off suddenly during an eclipse.

Study of the ionosphere is important because of the increasing use of long‐distance communication by radio. High‐frequency radio signals travel around the Earth in a series of giant bounces between the ground and the reflecting layers of the ionosphere, which range from about 50 to 250 miles in altitude. When these layers disappear or are disrupted, long‐distance communication by radio fails or is garbled.
Alibag Magnetic Observatory January to March, 1947
Authors: Rao M. P.
Published: February 2008

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

January 16–17—A sudden‐commencement disturbance began at 03h 27m GMT, January 16, and continued until about 01h, January 17. The initial stage of the disturbance was characterized by small fluctuations in all the three elements. One K‐index of 6 and one of 5 were recorded during the disturbance. Ranges: D, 5′.8; H, 153 gammas; Z, 58 gammas.
A proposed auroral index‐figure
Authors: Thomsen I. L.
Published: February 2008

Introduction—Even a casual observer of an auroral display notices changes either slow or fast, of what may be termed intensity or activity. Assuming cloudless skies, the complete description of a display would require trained observers to record continuously throughout the dark hours. Most of our knowledge of the Aurora Australis as seen from New Zealand, is obtained from numerous reports from voluntary observers, with all degrees of skill. By virtue of the human factor in the case of voluntary observers, some observations may be continuous and intense for perhaps two or three hours, while others may be “spot” observations merely stating that an aurora was seen at a certain time.
Final relative sunspot‐numbers for 1946
Authors: Waldmeier M.
Published: February 2008

Table 1 contains the final sunspot‐numbers for 1946 for the whole disk of the Sun, based on observations made at the Zurich Observatory, supplemented by series furnished by other cooperating observatories. Table 2 gives the number of spot‐groups on each day for the year 1946. The yearly mean of the group‐numbers is 7.8. The yearly mean of the relative‐numbers is 92.6, against 33.2 in 1945.
Geophysical Institute of Huancayo July to September, 1947
Authors: Ledig Paul G.
Published: February 2008

July 17mdash;At 17h 49m GMT, July 17, a sharp increase in H of 260 γ in a five‐minute period was noted, followed by a rapid decrease in intensity in the two and a half hours that followed to a minimum bay 620 γ below the maximum (which was registered at 17h 54m, 460γ above the base‐line value); this was followed by a moderate increase of 140 γ and a subsequent drop of practically the same magnitude in the next three hours, after which H continued active (showing small, rapid movements, and two deep bays and one moderate peak during the course of the next day), and at a subnormal value, slowly returning to normal in the next seventy‐two hours. At the time of commencement Z increased in value by 24 γ in a five‐minute period, decreasing to a minimum 56 γ below the peak in the next two and a half hours. D showed a sharp but small increase at 17h 49m and a maximum range of 5′.5 during the period of maximum activity.
Apia Observatory April to September, 1947
Authors: Beagley J. W.
Published: February 2008

(Latitude 13° 48′.4 S., longitude 171° 46′.5 or 11h 27m.1 W. of Gr.)

April 8–10—A marked sudden commencement at 21h 51m GMT, April 8, was followed by mild irregular movement with a gradual return to normal at 09h, April 10. K‐indices of 5 were recorded during the last three‐hour period of April 8 and the second of April 9.
Five International quiet and disturbed days for January to June, 1947
Authors: Scott W. E.
Published: February 2008

Reports of geomagnetic activity for the first six months of 1947 have been received from a sufficient number of observatories so that the international quiet and disturbed days can be selected in accordance with the method outlined on pages 219–227 in the December, 1943, issue of this JOURNAL, with the exception that the daily indices B based on the actual ranges of KA from seven American‐operated observatories are no longer available and hence this criterion is lost. The selection is based on the reports of magnetic character on a scale of 0, 1, and 2 from an average of 28 observatories and of K‐indices from an average of 24 observatories.
Sitka Magnetic Observatory October to December, 1947
Authors: Campbell Joel B.
Published: February 2008

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

September 30‐October 3—The magnetic disturbance which was reported in the last quarterly report as beginning suddenly at 18h 08m GMT, September 30, continued only moderately disturbed until 03h, October 2. However, after that time there was a sharp increase in storminess and for the following sixteen hours or until 19h, October 2, there occurred rather severe activity in the form of short‐period oscillations of varying amplitudes, superposed on small bays. Three K‐indices of 7 and three of 6 were recorded during this period. After a short lull‐period there was another increase in storminess and between 03h and 10h, October 3, three K‐indices of 7 were recorded. The storm began to die out at about 12h, October 3, and may be said to have ended three hours later.
Critical frequency near τ = 1
Authors: Eckersley T. L.
Published: February 2008

There can be no doubt that there are two critical frequencies in the extraordinary ray. The normal critical frequency is in the region where the rays are lost and is the larger of the two. The extra critical frequency is in the neighbourhood of τ = 1. But experimenters, especially Berkner and Booker (B and B), previously in America, and Martin and Munro (M and M) in Australia, are agreed that it is rather less than τ = 1.
The abnormal daily variation of horizontal force at Huancayo and in Uganda
Authors: Chapman S.
Published: February 2008

(1) Huancayo—The establishment of a magnetic observatory at Huancayo, Peru (12° 03′ south, 75° 20′ west), by the Carnegie Institution of Washington, was soon rewarded by a remarkable and totally unexpected discovery. This was the abnormally large amplitude of the solar daily variation S of horizontal magnetic force (H) at that station. Later it was found that the lunar daily variation of H was also abnormally large. The other two magnetic components, vertical and east force, showed no such abnormality at Huancayo.
A Panoramic Ionospheric Echo Recorder
Authors: Stoffregen W.
Published: February 2008

In the following is described an automatic radio echo transmitter‐receiver in which the panoramic principle commonly used in radar is employed with some modifications. By means of the oscillograph arrangements connected to the receiver one thus obtains a standing picture of the reflections from the ionospheric layers on the screen of a large cathode‐ray tube with long afterglow. By this method of recording it is therefore possible to study rapid changes in the degree of ionisation of the various layers, and sporadic layers of short life‐time may he detected anti studied.

The Panoramic Ionospheric Echo Recorder is of especial interest where a study of ionospheric problems in connection with magnetic disturbances and aurora at places in high latitude is contemplated, and recorders of this type will be placed at several stations in Norway for the purpose of carrying out such investigations. The recorder is also intended to be used at some of the important short‐wave receiving stations, which are interested in at any time obtaining a survey of the ionospheric conditions.
Sitka Magnetic Observatory April to June, 1948
Authors: Campbell Joel B.
Published: February 2008

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

April 22—A moderate disturbance of short duration began gradually at about 00h GMT, April 22, and continued until about 18h of the same date. The most disturbed portion occurred between 12h and 13h, when there was violent activity in the form of short‐period, large‐amplitude oscillations. A K‐index of 8 resulted from this activity.
Tucson Magnetic Observatory April to June, 1948
Authors: Nelson J. H.
Published: February 2008

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

April 6–7—At 03h 57m GMT, April 6, there was a momentary depression of about 2 gammas in H, followed immediately by a rapid 36‐gamma increase to mark the sudden commencement of a moderate storm. Simultaneously with the changes in H, smaller disturbances began in D and Z. During the first thirteen hours the storm activity was very mild, with small ranges. Intensity of the disturbance increased a little just before 17h, with pronounced short‐period moderate‐amplitude variations in D and H. A square bay in H was recorded between 18.2h and 19.7h. Activity continued, decreasing slightly in intensity until the end of the storm about the middle of the Greenwich day, April 7. Range in H was 97 gammas.
On the concentration of condensation nuclei in the air over the North Atlantic
Authors: Hess Victor F.
Published: February 2008

On account of the scarcity of data on the number of nuclei over the oceans, I thought it would be interesting to carry out new measurements of the nucleus content of the air during a voyage from New York to Le Havre, France, and back, aboard the SS America of the United States Lines. The last observations in the North Atlantic were made between 1928 and 1934. It seemed also worth while to see if the contamination of the atmosphere had increased since that time.

The instrument used was an Aitken pocket dust counter (modified model, after G. Luedeling), which was recalibrated according to the findings of V. F. Hess and C. O'Brolchain [see 1 of "References" at end of paper].
Changes in ionization and radio reception during the sunspot‐period 1944–1947
Authors: Stetson Harlan T.
Published: February 2008

If 12‐month running means of critical frequencies are taken to eliminate seasonal effects, a close correspondence exists between critical frequencies for both the E‐ and F‐layers and sunspots. Since the ultra‐violet light of the Sun is assumed to be the major ionizing agent, this increase in ionization with sunspots during the night hours presents some interesting cosmic problems as to the cause and the maintenance of ionization on the unilluminated half of the Earth.

Standardized measurements of field intensities of the Bureau of Standards standard‐frequency signal, WWV, have been recorded at the Cosmic Terrestrial Research Laboratory at Needham during recent years for the 5‐, 10‐, and 15‐Mc frequencies. Curves of night fields of WWV‐5‐Mc show that during the rise of sunspots from 1945 to 1947 the average values recorded between 22h and 02h rose from 300 microvolts to 900 microvolts when the Zurich sunspot‐nurnber of 105 was reached; thereafter, field intensities decreased in value as sunspot‐numbers continued to rise to a maximum of 150, a value reached last year. The decline in field strength with very high sunspot‐numbers is attributed to attenuation introduced by increase ionization of the lower layers. Day fields, representing averages of observations between 10h and 14h showed a steady decline with increasing sunspots, a fact which is again explained on the basis of increasing absorption in the lower layers. The changes in the daytime field were from 225 microvolts when the sunspot‐number was 20 to about 15 microvolts when sunspot‐numbers were 150.

For the 10‐Mc reception day fields rose from a value slightly in excess of 90 microvolts, when the sunspot‐number was 80, to values of 260 microvolts or more, when sunspot‐numbers registered from 140 to 150. Night fields on the 10‐Mc frequency, based on observations between 22h and 02h, rose from 10 microvolts, with sunspot‐number of 80, to values in excess of 30. microvolts, with sunspot‐numbers between 140 and 150.

Observations on the broadcast band of Station WBBM, Chicago, 780 kc, received at Needham, a distance of 851 miles, show a general decline in field intensities from values in excess of 270 microvolts to values of but 45 microvolts as sunspot‐numbers increased from 20 to a maximum value of 150.
Committee on characterization of magnetic disturbances, International Association of Terrestrial Magnetism and Electricity
Authors: Bartels Julius
Published: February 2008

(1) Dr. J. Veldkamp, De Bilt, has notified the President of our Association, Professor S. Chapman, Oxford, that the collection, reduction, and printing of character‐figures and three‐hour‐range indices can be taken up, from January 1, 1949, at the Kon. Nederlandsch Meteorologisch Instituut under the same conditions as before, namely, that the cost of printing and shipping the publications is paid by the Association. He feels certain that the sum of $2,000 set aside for the next three years will be sufficient.

(2) When, at the Oslo Meeting, it was not certain whether De Bilt was in the position to serve as Dr. van Dijk had done for so many years, Professor Lahay had kindly volunteered to establish the (C + K)‐center at Uccle. The President has informed Professor Lahay of De Bilt's definite offer; in reply, Professor Lahay said that he considered it as a matter of course that the (C + K)‐center should be at De Bilt.
Geophysical Institute of Huancayo April to September, 1948
Authors: Giesecke Albert A.
Published: February 2008

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

April 6—A sudden‐commencement type of storm was recorded at 03h 59m GMT, April 6, with a rapid increase in H of about 36 gammas, an increase in Z, and a slight decrease in D. This sudden change was followed by relative tranquility until 16h 53m, when all elements showed pronounced activity. H increased about 122 gammas and was followed by rapid oscillations of an amplitude averaging about 40 gammas, reaching a peak‐value at 18h 02m of 325 gammas above the base‐line, and thence rapidly decreasing to a minimum at 18h 22m, 170 gammas below the base‐line. The vertical component Z also increased sharply some 15 gammas at 16h 53m, while D was likewise increasing almost 3′.
Hermanus Magnetic Observatory July to September, 1948
Authors: van Wijk A. M.
Published: February 2008

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

July 26—A small crochet appeared on the traces at 08h 38m GMT, July 26. Minor disturbances were recorded during the ensuing six days.
Die Verteilung des erdmagnetischen Potentials in Bezug auf beliebige Durchmesser der Erde
Authors: Schmidt Ad.
Published: February 2008

In einem vor drei Jahren gehaltenen, im verflossenen Frühjahre veröffentlichten Vortrage1 hat Herr von Bezold darauf aufmerksam gemacht, dass die Mittelwerte, die das magnetische Potential auf den einzelnen Parallelkreisen annimmt, mit sehr grosser Annäherung dem Sinus der geographishen Breite β, anders ausgedrückt dem Cosinus des Nordpolabstandes u proportional verlaufen. Indem er nämlich die Gesamtheit dieser Mittelwerte, das von ihm sogenannte normale Potential, mit Vn, die Abweichungen von diesem mit Van bezeichnet, so dass das ganze Potential V durch die GleichungV = Vn + Vabestimmt wird, findet er, dass mit R als dem Erdradius fastVn: R = K sin βzu setzen ist. Auf der Grundlage der von Quintus Icilius gezeichneten Karte des Potentials für die Epoche 1880,o ergiebt sich ihm K gleich 0,330 cm−½ g−½ s−1, während die mittlere Abweichung der Function K sin β von Vn : R nicht grosser als ± 0,0029 cm−½ g½s−1 wird.

Es liegt die Frage nahe, ob die Rotationsaxe der Erde in dieser Hinsicht vor ihren übrigen Durchmessern ausgezeichnet ist oder ob etwa bei einem unter diesen die entsprechend gebildeten Abweichungen noch geringer ausfallen. Mit Rücksicht auf die verschiedentlich, vor allem auch in der genannten Abhandlung bemerkte Möglichkeit eines Zusammenhangs der erdmagnetischen Erscheinungen mit der Rotation der Erde kann eine exacte Beantwortung dieser Frage, gleichgültig, in welchem Sinne sie auch ausfallen mag, einiges Interesse beanspruchen.
Ueber die Frage, in welcher Form die magnetischen Observatorien ihre Ergebnisse veröffentlichen sollen
Authors: Eschenhagen M.
Published: February 2008

Es ist sicher die Frage von Wichtigkeit, in welcher Form die magnetischen Observatorien ihre Ergebnisse veröffentlichen sollen, ob man Polarcoordinaten oder rechtwinklige Coordinaten zur Darstellung der Variationen der erdmagnetischen Kraft wählen soll; wichtiger aber erscheint mir die Vorfrage, in welchem Umfange sollen die unmittelbaren Beobachtungsergebnisse in den Jahrbüchern veröffentlicht werden. Gewiss ist es höchst nützlich für einen Bearbeiter, gleich die tägliche Periode, z. B. der rechtwinkligen Componenten, dargestellt durch 24 Stundenwerthe oder noch besser durch die Coefficienten der trigonometrischen Reihen, gedruckt zu finden, aber zunächst ist doch die Frage zu lösen, welches Material soll diesen Ableitungen zu Grunde gelegt werden. Sollen ungestörte Tage ausgewählt werden, so müssten dieselben für alle Observatorien dieselben sein, sie müssten also nach vorherigem Einverständniss ausgesucht werden. Allein würden nur diese Tage publicirt, so würden Untersuchungen nach anderen Richtungen unmöglich gemacht werden.
A summary of the results of the recent magnetic survey of Great Britain and Ireland conducted by professors Rücker and Thorpe: Part III. On the relation between the magnetic and the geological constitution of Great Britain and Ireland
Authors: Rücker A. W.
Published: February 2008

In the memoir of which this paper is a brief summary we have carefully distinguished between the problem of determining the positions of the loci and centers of magnetic disturbances, and that of explaining the means by which the Disturbing Forces are produced. On the latter point there may be some difference of opinion.

The most probable causes of the Forces are electrical Earth currents and magnetic rocks, or both of these combined. It may be desirable to give an outline of the evidence which leads me to believe that the presence of magnetic rocks is the more potent of these sources of disturbance.