bluuebunny/crossref_metadata_2025_split huggingface dataset:
William Bullock Clark
Authors: Bauer L. A. 
Published: February 2008

While Professor William Bullock Clark was chiefly known for his notable contributions to the advancement of geological science, he is also to be credited with having taken a prominent part in the advancement of terrestrial magnetism and other geophysical subjects. It was owing to his kindly interest and stimulating appreciation that the writer of this biographical sketch was given the means and the opportunity, under the auspices of the Maryland Geological Survey, to carry out a detailed magnetic survey of Maryland (1896–1899).The example set by Professor Clark was soon followed by the State Geologist of North Carolina, and in 1899, the time appearing ripe to the Superintendent of the United States Coast and Geodetic Survey (then Dr. H. S. Pritchett) for the reorganization of a magnetic survey of the United States along the general lines of the Maryland magnetic survey, the writer was invited to draw up a plan and take charge of such a survey. The experience gained in the latter work led the writer some years later to propose a plan to the Trustees of the Carnegie Institution of Washington for a general magnetic survey of the Earth, which plan, as is well known, has been in actual execution since 1904. Thus the magnetic survey of Maryland may be considered as having been virtually the forerunner of the reorganized magnetic survey of the United States and of the general magnetic survey of the Earth.
Results of observations made during the solar eclipse of June 8, 1918, at the magnetic observatory at Antipolo, Manila
Authors: Masó M. Saderra 
Published: February 2008

Table 1 shows the magnetic elements as well as the meteorological conditions, during the eclipse of June 8, 1918. The magnetic ordinates were read from the photographic records with the greatest accuracy every five minutes; the values of the base lines are only approximate. At the time the daily mean absolute values of the different magnetic elements were:Declination, D = 0° 34′.09 E; Horizontal Intensity, H = 38110γ; Vertical Intensity, Z = 10975γ.
Additional results of Earth‐current observations at Jersey, England
Authors: Deschevrens Marc 
Published: February 2008

I am persuaded that the new facts which I have derived from the continued study of my observations of a subterranean electric current at Jersey, since I sent you the notes in January and February last, will clear away more than one of the objections which may be raised either regarding the manner of capturing the earth‐current without an aerial wire, or to the first and curious results which it has furnished.The diurnal variation of two nearly equal oscillations which I obtained from my first observations is and should be of the same form as the diurnal variation in height of the water in a seaport open to the ocean tide. Twice in 24 hours the port is filled and emptied alternately, and these two oscillations of the sea are perceptibly equal in a given day. The variation of the potential observed at Jersey is a veritable electric tide which is produced in the Earth's crust parallel to the ocean tide at its surface.
The magnetic storm of August 11–12, 1919, as recorded at Buitenzorg, Java
Authors: Visser S. W. 
Published: February 2008

The conditions prior to the appearance of the storm were those of a magnetically quiet day.Sudden Commencement. Time, Aug. 11, 6h 58m.5 G.M.T.; X increases sharply by 165γ; Y swings to the west (faintly), to the east (declination 1′), and to the west (declination 7′); and Z increases sharply by 29γ.
The Aurora Borealis of March 22–23, 1920, as seen at the Cheltenham Magnetic Observatory
Authors: Hartnell Geo. 
Published: February 2008

Another magnetic storm of extraordinary magnitude was recorded on March 22–23, 1920, at the magnetic observatory of the United States Coast and Geodetic Survey, Cheltenham, Maryland, latitude 38° 44′.0 N., longitude 76° 50′.5 W. Its chief features are described in Mr. Hazard's article, pages 57–59. There was no recurrence of the storm 27 days later, April 19–20.The Aurora was visible soon after sunset on March 22, 1920, but was first noticed by the writer at 8h 05m 75th meridian time. At 8h 10m a display of rays developed, proceeding from a bright band low in the northern horizon some 45° in extent. The rays were visible from a point in the western horizon a few degrees (5°–10°) N. of the new moon (azimuth from S ‐ 88°) to a few degrees in the eastern horizon east of Arcturus (azimuth = −76°.0), and apparently converged to a few degrees north of the planet Jupiter (azimuth 26.5 and altitude 68°.5). There was a conspicuously rosy colored ray in the east. The rays lasted for about 5 minutes. The boundary of the illuminated area was parabolic in form. The ray display was followed by a general diffused glow.
Preliminary results of ocean magnetic observations on the Carnegie from St. Helena to Cape Town and thence to Colombo, Ceylon, April to June, 1920
Authors: Ault J. P. 
Published: February 2008

NOTES ON TRIP FROM ST. HELENA TO CAPE TOWN.We sailed from St. Helena at 3 P. M., April 3, and after three days of sailing in the southeast trade winds we entered the region of variable winds and calms on April 6. Considerable lightning accompanied by heavy thunder was noted during some heavy squalls in the middle of the South Atlantic Ocean, far from land. By April 11 we had crossed this region of variable winds and had picked up the westerly winds. A moderate to fresh gale blew from the northwest, shifting to southwest, during April 13 and 14.
Magnetic storm of August 11, 1919, at Vassouras Magnetic Observatory
Authors: Lemos A. 
Published: February 2008

(Latitude: 22° 23′ 57″ S; Longitude: 43° 39′ 00″ W of Gr.)Declination (D).—The sudden commencement was at 7h 00m, G. M. T., there being a fall of 5′, followed by a series of rapid oscillations, superposed on others of greater period and irregularity. The greatest value, 11° 19′.0 W, occurred at 8h, G. M. T., and the minimum, 10° 59′.0 W, at 15h 54m. The extreme range of the variation was thus 20′. At 21h, the disturbance diminished in intensity; it disappeared completely at 19h 07m on August 12. From this time until 11h 00m, on August 13, the value of the declination remained constant at 11° 12′.0 W.
Note on a simple measure of the Earth's daily magnetic activity
Authors: Bauer Louis A. 
Published: February 2008

In a timely paper1 for the Rome meeting of the International Section of Terrestrial Magnetism and Electricity, Dr. G. van Dijk, of the De Bilt Observatory, makes a very desirable comparison, chiefly for the year 1915, of measures of terrestrial magnetic activity proposed by various investigators. For the various measures, designated below, the following symbols are used here: D, magnetic declination; H, horizontal intensity; Z, vertical intensity; R, absolute diurnal range, or difference between extreme daily values of element considered; and A, diurnal range of hourly values (mean value over 60‐minute interval).If at any observatory the diurnal ranges of D and H are not available, then those of the rectangular components X and Y are to be used. In the second, third, and fourth measures the D‐range is to be expressed in gammas, namely, H RD
Periodicity of activity in terrestrial magnetism [Comment on article by Dr. G. Angenheister]
Authors: Chree C. 
Published: February 2008

Having been myself recently engaged in a discussion1 of the 27‐day “period” in magnetic disturbance, I read with interest Dr. G. Angenheister's paper on “Periodicity” in your recent issue.2 With some of his conclusions my own investigations are in harmony, but others of his conclusions seem to me hardly warranted by the facts. I shall presently explain my reasons for dissent, employing for the purpose the data in the accompanying table, but a few preliminary remarks are desirable on the nature of the international “character” figures of which Dr. Angenheister and I have both made considerable use in our investigations.As is, I think, well known to all who have considered these figures closely that while they discriminate admirably between the days of a single month, they suffer from the drawback that the significance possessed by the same numeral in different seasons is not the same. In a quiet year the figure 1.8, for example, connotes usually less disturbance than it does in a disturbed year. The years 1911–14, which contain a number of the “great” storms in Angenheister's Tables 1 and 2, l.c. pp. 64, 65, were, on the whole, very quiet years, and some of the storms of those years to which “character” figures of 1.8 or 1.9 were assigned were quite ordinary storms.
On the diurnal variation of the potential gradient of atmospheric electricity
Authors: Mauchly S. J. 
Published: February 2008

New observations obtained aboard the Carnegie during the year ending November, 1921, increased by 50 per cent the observational data regarding the diurnal variation of the potential gradient over the oceans. A separate analysis of the new data has confirmed the results announced by the author in 1921 regarding the predominance, over the oceans, of a 24‐hour wave progressing approximately according to universal rather than local time. It is found, however, that at least in the Pacific, there is also a well‐defined secondary wave during the months of northern summer.The present investigation has been extended to include also the diurnal variation of the potential gradient over the several continental areas. From harmonic analyses of the diurnal variation from many widely separated stations, varying in latitude from 78° north to 77° south, it is found that, despite the greater complexity of the variation over land, a large percentage of the stations considered show sufficiently good agreement with the ocean results to furnish strong evidence for the assumption of a world‐wide effect of 24‐hour period progressing approximately according to universal time. The average amplitude of this wave is about 20 per cent of the mean‐of‐day value and the average time of its greatest phase apparently varies somewhat with time of year, ranging from about 16h to 19h G. M. T.While there are land stations in the tropical and temperate regions for which the analytical results are not in accord with the foregoing, there is considerable evidence indicating that this may be due to local disturbances of large amplitude rather than to an absence of the general phenomenon. The fact that for ϕ2, the phase angle of the 12‐hour wave at local midnight, marked departures from the all‐stations mean are largely confined to places where the amplitude of the secondary wave is relatively small lends further support to the view that the limitations of harmonic analyses in the form here used may be partly responsible for the lack of more complete agreement between the land and ocean results.
General description of the Earth‐current measuring system at the Watheroo Magnetic Observatory
Authors: Gish O. H. 
Published: February 2008

The paper consists essentially of two parts, the first being an analysis setting forth the general requirements for the determination of the earth‐current density vector, and the second a description of the outstanding features of the system installed at the Watheroo Magnetic Observatory (in Western Australia) for measuring the potential gradient of earth currents.General requirements.—A complete description of earth currents requires a knowledge of the distribution of, (1) the earth resistivity, and (2) the earth‐current potential. A method suitable for determining the former is indicated. The major portion of the analysis, however, deals with the potential gradient. It is first indicated that a “potential survey” should be made in the vicinity of earth‐current lines in order to locate and measure any discontinuities that may exist in the potential field. General methods of approximately determining the potential gradient at a point are then given. The relations for resolving and combining earth‐current potential measurements are developed in such a manner as to include the less favorable case where the lines are not at right angles to each other.The earth‐current lines at Watheroo are so arranged that the earthed points determine a right angle, one limb of which extends due east and the other due north from the vertex. The point at the vertex is used as a common point of reference for the potentials of the other points. Two other points on each limb are situated, at present, 1.6 km. and 3.2 km. distant, respectively, from the common point. The potential difference between the common point and the nearer point on each branch can be alternately recorded by means of overhead and underground systems, and thus a close comparison of the relative virtue of these two types of line may be made. Only overhead lines connect with the farther point on each line. The overhead lines possess no features of special interest. The underground lines consist of leaded rubber‐covered copper conductors in bituminized fiber conduit, placed at a depth of 46 cm. below the earth's surface. For other details, reference may be made to the complete article.
Report on magnetic observations by the Carnegie Institution of Washington during the total solar eclipse of September 10, 1923
Authors: Ault J. P. 
Published: February 2008

This paper presents a report on special magnetic observations made by the Carnegie Institution of Washington at Point Loma and Mt. Wilson, California, and at Guatemala City, Guatemala, during the solar eclipse of September 10, 1923. At Point Loma, magnetic declination, horizontal intensity, and inclination observations were made, while at the other two stations only declination observations were made.Methods and instruments similar to those used during previous eclipses were employed, and the eclipse effects on the Earth's magnetic field were similar to those previously observed. The usual diurnal variation in the Earth's magnetism was interrupted, the change amounting to from 1′.5 to 3′ in declination, 60γ in horizontal intensity, and 1′.5 of inclination. A complete analysis and discussion must await; the receipt of data from other observatories located near the belt of totality.
Atmospheric‐electric observations during the total solar eclipse of September 10, 1923
Authors: Johnston H. F. 
Published: February 2008

The Department of Terrestrial Magnetism made observations of potential gradient, positive conductivity, and negative conductivity at Point Loma near San Diego, California, on September 10, 1923, as well as control observations on the four preceding and following days. Improved bifilar electrometers, which gave dependable determinations of potential, were used. Potential gradient was observed both by eye‐readings and by continuous photographic registration. Conductivity was observed simultaneously with two Gerdien conductivity apparatuses. Meteorological conditions were very steady for the day of the eclipse; there was a total range of 2°.5 Centigrade in temperature, 9 per cent in relative humidity, and 0.02 inches in barometric pressure.During the 20 minutes following totality, the temperature decreased 0°.8 Centigrade, and the relative humidity increased 3 per cent. The sky was completely overcast with fog which extended above 17,000 feet. Observational irregularities due to leak on account of increased humidity or alteration of instrumental constants caused by changes in temperature were smaller than the errors of observation. It was found that the potential gradient for about half an hour immediately following totality was about 15 per cent subnormal. The electrical conductivity of the air and the air‐earth current‐density increased about 10 per cent above normal during the 10‐minute period following totality. These results are in close agreement with those observed by the Department of Terrestrial Magnetism at Lakin, Kansas, on June 8, 1918, and at Sobral, Brazil, on May 29, 1919. There was a greater increase in the negative conductivity than in the positive conductivity of the order of 15 per cent.
The radium‐emanation content of sea air from observations aboard the Carnegie, 1915–1921*
Authors: Mauchly S. J. 
Published: February 2008

Observations for determining the radioactive content of the air have been regularly made aboard the yacht Carnegie, when at sea, since 1909. From 1909 to 1914 the Elster‐and‐Geitel method was used, and the results obtained have been published elsewhere. Since 1915 observations for absolute determinations have been made aboard the vessel using an adaptation of the Gerdien aspiration method. A summary is given of the final results of nearly 400 observations for the period 1915 to 1921, showing in considerable detail the distribution of radium emanation over each of the major oceans.The mean value of the radium‐emanation content over the oceans resulting from all the observations is 2.6 × 10−18 curies per cubic centimeter. However, if observations which clearly show the effects of nearby land are excluded, the mean value of 1.2 × 10−18 curies per cubic centimeter is obtained from the remaining 333 observations. These results fully confirm the earlier conclusions of Simpson and of Swann to the effect that the radium emanation normally present in sea air well removed from land is entirely inadequate for producing the atmospheric ionization found in these regions. They do not support Bongards' suggestion that an appreciable portion of the radioactive content of the Earth's lower atmosphere is of solar origin.
Records of principal magnetic storms and of earthquakes at the Watheroo Magnetic Observatory, July 1 to December 31, 1924
Authors: Johnston H. F. 
Published: February 2008

(Latitude, 30°19′.lS.; Longitude, 115°52′.6 or 7h 44mE. of G.)October 22 to 25, 1924.—This severe storm began with a sudden decrease in all three elements. A large wave in horizontal intensity occurred about 7h on October 23 with a range of 74γ in 23 minutes. A large sweeping movement in horizontal intensity with small but rapid waves lasted from lh to 10h on October 24. During the next hour there was a rapid recovery of 70γ toward the normal curve. There are simultaneous bays in all three elements at 7h.0 and 21h.6 on October 23, at 22 h on October 24, and at 10h and 12h.8 on October 25.
Principal magnetic storms recorded at the Apia Observatory, July to December, 1925
Authors: Thomson Andrew , Westland C. J. 
Published: February 2008

(Latitude, 13° 48.′4S.; Longitude, 171° 46′ or 11h 27m.1W. of Greenwich.)Notes.—On September 21 the minimum in H is 35090γ, the lowest value recorded since 1921. The storms on September 21 and .24 begin with sharply defined motions, upward and almost perpendicular, signifying increase of intensity. On August 23 the commencement is downward, and is rather less clearly defined than in the storms at the end of September. The smaller storm on September 2 is merely the strongest part of a prolonged disturbance, and the times given are only approximations.
A vertical‐intensity magnetometer
Authors: la Cour D. 
Published: February 2008

Magnetic observations, and in particular those necessary for the control of magnetograph records, at stations in high magnetic latitudes have been greatly handicapped, because of unfavorable magnetic conditions as well as temperature conditions at such stations, for lack of a suitable instrument to determine rapidly and with precision the vertical intensity of the Earth's magnetic field. The establishment of the Godhavn Magnetic Observatory in Greenland, where the magnetic inclination is about 82°, led the author to consider electrical methods of determining the magnetic vertical‐intensity of the Earth's field. An experimental apparatus was used during a trip to Greenland in 1925 to select a site for the Observatory, and as a result of these experiments a new type of vertical‐intensity magnetometer was developed and was sent in August 1926, after trial at the Rude Skov and Potsdam observatories, to the Godhavn Observatory for use there regularly.The essential part of the new instrument is a precise standard for mutual inductance, that is, an inductor with two sets of windings, and very strongly built, By rotaiing the standard 180° on a horizontal axis the vertical intensity of the Earth's magnetic field gives rise to electromotive forces in the windings. One winding is connected with a ballistic galvanometer which, through the arrangement described below, measures the induced effect; the sensitivity of the galvanometer is such that rotating the inductor 180° would cause a deflection quite beyond the scale‐limit of the galvanometer, for example, at Rude Skov for a scale‐distance of 2 meters, a deflection of 10 meters. This arrangement, a sort of zero‐method, by which the deflection of the galvanometer never exceeds a few centimeters even for highest sensitivity of the apparatus, utilizes an accurately determined electric current which, during the turning of the inductor, may be made or broken in the second winding. The making or breaking in this current through the second winding induces an electromotive force in the winding connected with the galvanometer, and the connections are such that the electromotive force induced by the variation of the “compensating current” is opposite to the electromotive force induced by the vertical component of the Earth's magnetic field during a turn of the inductor. Thus, the resulting deflection of the galvanometer corresponds to the difference of the two induced electromotive forces. By again turning the coil and using some other compensating current, a second galvanometer reading is obtained. By means of two such readings the strength of a compensating current, which should give just the zero‐deflection of the galvanometer, is readily computed.
Note on declination base‐line control at the Godhavn Observatory, Greenland
Authors: la Cour D. 
Published: February 2008

Dr. Olsen, in charge of the Godhavn Observatory, has sent an example to show how well the special arrangement for time‐marking in use at the Observatory for determination of base‐line value of one of the declination variometers is functioning. The scalings and record are for August 9, 1926. I have now measured the photographic record and reduced its readings; the results are given in the following table, which may be of interest in showing how the Godhavn Observatory is able to make precise determinations of base line despite the nearly continuously changing magnetic field.It appears from the tabulation that the actual range in the five observations for the first position of the magnet was 30′ 15″, and for the second position of the magnet 3′ 37″; the actual photographic record during the period of observation shows much more pronounced movements of the magnet. Thus it will be seen that, despite the generally magnetically disturbed conditions prevailing at Godhavn, the methods in use there permit determination of declination base‐line values with a precision quite comparable with that obtained at observatories in lower magnetic latitudes. This is in a large measure due to the special time‐marking arrangement by which the instant of absolute observation is definitely marked on the magnetogram. There is reason to hope that the determination of the base‐line values for horizontal intensity and vertical intensity at the Observatory will be likewise satisfactory.
Principal magnetic storms and earthquake disturbances recorded at the Huancayo Magnetic Observatory, January 1–31, 1927
Authors: Goddard Richard H. 
Published: February 2008

(Lat. 12° 02′.7 S.; long. 75° 20′.4 W. or 5h 01m W. of Gr.)January 1, 1927.—A sudden commencement indicating an increase in horizontal intensity of 22γ began at 8h 47m and ended at 8h 50m. A change of 0′.5 in a westerly direction was shown in declination and an increase of 2γ in vertical intensity.