bluuebunny/crossref_metadata_2025 huggingface dataset:
Two new types of magnetometers Department of Terrestrial Magnetism of the Carnegie Institution of Washington
Authors: Fleming J. A.
Published: February 2008

The land operations of the Department of Terrestrial Magnetism of the Carnegie Institution of Washington especially in regions more or less difficult of access, have emphasized the need of more portable and more compact instrumental outfits than heretofore in general use, without at the same time sacrifice in requisite accuracy. For the regions here considered, in which the greater part of our work must be done, travel is usually difficult and a bulky and heavy equipment is, accordingly, a serious obstacle to safe transportation and rapid work. The conditions imposed make imperative also the omission of complicated and intricate mechanical devices, the adjustments of which are generally difficult to make and maintain, as well as the avoidance of a great number of loose accessory parts, the loss of any one of which may mean at times either the discontinuance or at least the serious interruption of a campaign. Another essential feature in work of this kind is that the outfit be such to admit advantage being taken of every opportunity for observations ; the construction therefore should permit practically immediate use and not require what may be the best part of the available time for setting up and assembling various parts.
Ueber den elektrischen strom Erde‐Luft und seinen zusammenhang mit den Erdströmen und dem schwankungen des erdmagnetischen Feldes
Authors: Gockel Von Dr. A.
Published: February 2008

Die Frage, ob ein Teil des magnetischen Erdfeldes seine Entstehung den in der Erde oder den zwischen der Erde und der Atmosphäre circulierenden elektrischen Strömen seine Entstehung verdankt, ist in neuerer Zeit vielfach behandelt worden.

Man hat nach Zusammenhängen zwischen den Schwankungen des Potentialgefälles1 und denen der magnetischen Grössen gesucht. Zölss2 hat auf einen solchen zwischen dem Gang der Leitfähigkeit und der Deklination aufmerksam gemacht. Es ist aber klar, dass, wenn ein ursächlicher Zusammenhang zwischen den elektrischen und magnetischen Elementen überhaupt existiert, er in erster Linie zwischen den letzteren und dem elektrischen Vertikalstrom und nicht dessen einzelnen Komponenten existieren muss. Leider lagen von der doch weitaus wichtigsten luftelektrischen Grösse, dem elektrischen Vertikalstrom, bis in die neueste Zeit herein nur vereinzelte Bestimmungen vor. Man hat sehr häufig das Potentialgefälle, in neuerer Zeit nicht viel weniger häufig die elektrische Leitfähigkeit oder den lonengehalt der Atmosphäre gemessen, aber nur von sehr wenigen Observatorien sind Beobachtungen veröffentlicht, aus denen sich das Produkt von Potentialgefälle und Leitfähigkeit, der Vertikalstrom, berechnen lässt. Ganz vereinzelt nur wurden direkte Messungen dieses letzteren gemacht.
Magnetische Störungen, Feb. 3–4, 1912
Authors: Meyermann B.
Published: February 2008

Der Magnetograph des Observatoriums in Tsingtau verzeichnete am 3 und 4 Februar 1912 zwei Störungen, die eine auffallende Aehnlichkeit miteinander besitzen und auch dadurch von Interesse sind, dass sie fast zur gleichen Tageszeit auftraten. Charakteristisch sind bei beiden die Pulsationen, die etwa 1 Stunde vor Beginn des Anwachsens der H. I. auftreten, dann wieder verschwinden und erst wieder mit der betrachteten Störung einsetzen. Diese selbst zeigen ein rasches Anwachsen der H. I. und ein langsameres Abnehmen. Sie gleichen einer am 5. Oktober 1911 hier registrierten Störung, die jedoch nicht von Pulsationen begleitet ist.
Magnetic observations on the day of the solar eclipse of April 17, 1912, at De Bilt
Authors: Van Dijk G.
Published: February 2008

With reference to the article by Mr. O. H. Tittmann1 concerning the solar eclipse of April 28, 1911, it seems to me of interest to give here some communications about the magnetic registrations at De Bilt (Lat. 52° 6′N., Long. 5° 11′=0h 20m 44s E. of Gr.) at the time of the solar eclipse of April 17, 1912.

The magnetic condition of the Earth in April, 1912, may be inferred from the following list, containing the mean magnetic character (scale 0, 1, 2 of Innsbruck) from April 6 to 25, computed from the data of 42 magnetic observatories given in “Caractère magnétique de chaque jour des mois Avril‐Juni, 1912”:
L'eclipse du 17 avril 1912 à Lu‐kia‐pang (Chine)
Authors: de Moidrey J.
Published: February 2008

M. Kalinowski, dans une récente communication1 relative à l'éclipse du 17 avril dernier, manifeste le désir de voir les observations d'une station plus orientale que Varsovie. Lu‐kia‐pang étant dans ce cas, je vous envoie copie des courbes très calmes de ce jour. J'y joins la courbe moyenne des trois éléments à Zi‐ka‐wei, en avril, moyenne de onze ans, à la même échelle.

dD. 1 mm.=0′.48 dH. 1 mm.=4γ.66 dZ.1 mm.=7γ.6
Regarding improvement of appliances for measurement of the Earth's magnetic elements by magnetic and electric methods
Authors: Bauer L. A.
Published: February 2008

On April 1, 1914, the Department of Terrestrial Magnetism of the Carnegie Institution of Washington enters upon the eleventh year of its existence, and in quarters specially designed for its various needs. In its new home (see Plate I), the requisite facilities are provided for coping, in as successful manner as possible, with the many problems of general physical interest, or of an experimental nature, continually arising in the course of such an undertaking as a general magnetic or an electric survey of the Earth. Here the attempt is made to supplement the existing agencies for observational research in cosmical and terrestrial physics by laboratory research.

The work at present being conducted in the subjects of terrestrial magnetism and atmospheric electricity, is mainly observational: Either the magnetic or electric elements are determined at suitably distributed points over the Earth with the view of obtaining, as accurately as possible, a knowledge of its general magnetic or electric condition (magnetic or electric surveys), or at a considerably smaller number of points are registered the variations to which the magnetic and electric elements are subject with time and with varying planetary and solar conditions (observatories). There are thus magnetic and electric surveys, and magnetic and electric observatories; but hitherto there has been no laboratory for the specific purpose of broad physical research in problems of common interest to observational and experimental work, in brief, the same kind of happy combination of laboratory and observational facilities as has already proved successful in other sciences, as in astrophysics, for example.
The free and forced vibrations of a suspended magnet: 1. Theory
Authors: Reid Harry Fielding
Published: February 2008

Perhaps the principal use of a suspended magnet, for which the constants of the magnet are required, is the determination of the strength of the magnetic field. For this purpose it is customary to determine the period of oscillation of the magnet about a vertical axis and to calculate the strength of the field as if the magnet were suspended at its center of gravity and as if this period were independent of the swinging of the magnet as a pendulum. This introduces an error in the result, which fortunately is very small. Magnets often oscillate at the times of earthquakes, the cause of which has been much discussed.
The theory of electrical dispersion into the free atmosphere, with a discussion of the theory of the Gerdien conductivity‐apparatus, and of the theory of the collection of radioactive deposit by a charged conductor
Authors: Swann W. F. G.
Published: February 2008

Riecke has shown that if a charged sphere is placed in a stream of air, it loses its charge at a rate given by

urn:x-wiley:00968013:media:tma3642:tma3642-math-0001
where Q is the charge on the sphere, n is the number per c. c. of ions of opposite sign to the charge Q, ν is the specific velocity of these ions, and e is the ionic charge.

The deduction of the expression (1) is not as simple as might at first sight appear, and it is necessary to be on one's guard against forming a proof which, while leading to the result (1), is unsound in principle; in fact, the expression (1) would not be true for quiescent air. It is only true, as Riecke has pointed out, when there is an air‐current of sufficiently high velocity to enable us to neglect the effects of diffusion, reformation, and recombination of ions. Riecke obtained the expression by calculating the paths of the ions under the combined action of the field and of the air velocity. In a previous communication I have shown that the expression is true for a uniformly charged wire, but, as far as I know, no general proof has been given that the relation holds when the air does not flow in parallel stream lines with uniform velocity, and when the charged body has any arbitrary shape. The truth of the result, under the conditions stated, seems, however, generally to have been assumed in consequence of the experimental fact that a freely exposed body loses its charge at a rate proportional to the charge. It is the object of the first part of this paper to give a proof for the general case.
The atmospheric‐electric observations made on the second cruise of the Carnegie
Authors: Hewlett C. W.
Published: February 2008

The atmospheric‐electric observations, of which an account is given in this report, were made in pursuance of the plan of work assigned to the Carnegie by Dr. Bauer, the Director of the Department of Terrestrial Magnetism of the Carnegie Institution of Washington. The observers received at all times the cordial support of Captain Peters, who, throughout the cruise, was in command of the vessel. The final reduction and discussion of the observations have been made under the direction of Dr. Swann.

Atmospheric‐electric observations on board a sailing ship are attended with peculiar difficulties, some of which up to the present have not been sufficiently overcome to insure the degree of accuracy obtained in similar work on land. Chief among these difficulties is that of finding the proper factor for the reduction of the observed values of the potential‐gradient, so as to obtain the values which exist in the undisturbed open. The changes which take place in the relative positions of the sails and yards with respect to the rest of the ship introduce variations into this redaction‐factor, so that it is necessary to determine the latter for several arrangements of the sails. On account of the flying spray in the air, it is rather difficult to secure proper Insulation in the potential‐gradient observations. The difference of potential between the points occupied by the two collectors is a rapidly fluctuating quantity on account of the rolling and pitching of the ship, so that if the collectors take up the potential of the air around them fairly rapidly, it becomes difficult to make an estimation of the mean value of the electroscope‐reading.
The mean value of a function of spherical polar coordinates round a circle on a sphere
Authors: Bateman H.
Published: February 2008

Some years ago von Bezold pointed out that the mean value of the magnetic potential round a parallel of geographical latitude is very nearly equal to a constant multiple of the cosine of the north polar distance. Shortly afterward Adolf Schmidt considered the problem of finding the diameter of the Earth for which the mean value of the magnetic potential round each small circle with the diameter as axis, approximates in the best way to a constant multiple of the cosine of the polar distance from one extremity of the diameter. Schmidt chose as the criterion for obtaining the best approximation the condition that the square of the difference between the two quantities just mentioned, when integrated over the whole Earth, should be a minimum.

While reading Schmidt's paper, in connection with some studies at the Department of Terrestrial Magnetism during the past summer, it occurred to me that it might be useful to have a simple formula for the mean value of a function round a circle on a sphere. Such a formula can be deduced without much trouble from the formulæ for the transformation of spherical harmonics in a transition from one set of polar coordinates to another. These formulæ have been given by Adolf Schmidt, but the particular theorem we are interested in is not explicitly mentioned in his paper. A more direct proof of the theorem may be obtained by using a certain property of potential functions, and is perhaps worth recording.
Solar radiation and terrestrial magnetism
Authors: Bauer L. A.
Published: February 2008

1. One of the foremost magneticians of the last century, after a lifelong and devoted study of the various phenomena of the “Earth magnetical,” said in a public address: “Viewed in itself and its various relations, the magnetism of the Earth cannot be counted less than one of the most important branches of the physical history of the planet we inhabit.” I shall endeavor to show briefly, in the paper which I have the honor to present before you, the rôle certain terrestrial‐magnetic phenomena may play in the study of the physical characteristics of our atmosphere, especially of those upper levels, 100 kilometers and more above us, to which man has not yet succeeded in sending his exploratory instruments.

2. Among the most striking of the Earth's magnetic phenomena is the diurnal variation which takes place chiefly during the daylight hours, and varies in its magnitude and general characteristics with geographic position with the season of the year, and with Sun‐spot activity. A preliminary mathematical analysis, made by Schuster and presented before the Royal Society of England in 1889, led to the conclusion that “the principal part of the diurnal variation is due to causes outside of the Earth's surface, and probably to electric currents in our atmosphere.” Furthermore, Schuster found “that the horizontal movements in the atmosphere which must accompany a tidal action of the Sun or Moon or any periodic variation of the barometer, such as is actually observed, would produce electric currents in the atmosphere having magnetic effects similar in character to the observed diurnal variation.” In brief, the hypothesis adopted by Schuster to account for the supposed electric currents, generated in the upper atmospheric regions, was the one first proposed by Balfour Stewart—that the necessary electromotive forces for the production and maintenance of the required electric currents are generated by the motion of masses of conducting air across the lines of the Earth's permanent magnetic field, chiefly of the vertical component, thus bringing into play Foucault currents.
Cruise of the Carnegie from South Georgia to Lyttelton, New Zealand, January 14 to April 1, 1916
Authors: Ault J. P.
Published: February 2008

I beg to transmit the following report of our trip from South Georgia to Lyttelton:

The Carnegie left South Georgia at 7 P. M., January 14, 1916, towed out of harbor against a heavy head wind by the steam whaler Fortuna. In the days that followed we realized that we were in climatic conditions quite different from what we had previously experienced. Icebergs appeared in increasing numbers, and fog was almost continuous. We will long remember January 18 as the only day during the entire trip of four months when we failed to obtain observations for the magnetic declination. The sun was visible for only three seconds during the entire day, giving no opportunity for observations.
The effect of lunar distance on the magnetic declination at Zi‐Ka‐Wei
Authors: Chapman S.
Published: February 2008

The March 1916 issue of the Journal, pages 25–26, contains an interesting letter by Father de Moidrey, S. J., on the “lunar‐diurnal variation of the magnetic declination at Zi‐Ka‐Wei.” The fact which he has brought to light proves, on examination, to be somewhat remarkable and unexpected. It relates to the solar‐diurnal1 amplitude of declination, defined as the difference between the elongations normally occurring towards sunrise and at mid‐day (occasional maxima or minima at other times, due to disturbances, are neglected). The values P, A of this diurnal amplitude at the times of lunar perigee and apogee, respectively, were determined from three cycles of 10 or 11 years each.
Preliminary report on the results of the Aurora‐Borealis expedition to Bossekop in the spring of 1913. (fifth communication.)
Authors: Störmer Carl
Published: February 2008

1. In this Journal for September, 1913, March and December, 1915, and June, 1916, I published preliminary reports on my aurora‐borealis expedition of the spring of 1913. The present communication relates to the material of the last two nights, March 30 and April 1, 1913, comprising about 90 auroral photograms.

Fig. 1 shows the distribution of calculated altitudes of auroras above the surface of the Earth. These altitudes are not as concentrated around the 100 km. level as in the corresponding cases of March 14–15 and 16 to 29, mainly owing to the fact that the auroras of April 1–2 were all very faint and relatively tranquil.
Diurnal and annual variation of magnetic bays at Zikawei, 1877–1908
Authors: de Moidrey J.
Published: February 2008

The Bulletin Magnétique de Zikawei has been publishing, since the service was transferred to Lukiapang, a summary of the perturbations which Dr. C. Chree has designated as bays, that is, those which consist in a single oscillation such that the curve resumes afterward approximately its former position, the bay being entirely on one side of what would have been the normal curve. It has seemed well to investigate such bays in the magnetograms obtained at Zikawei during the period March 1877 to March 1908.

I. Diurnal variation. The time is noted when the greatest departure of the bay from the normal position occurs. The number of such occurrences is determined for each hour of the day for the whole period; 0h. 5 denotes the interval from 0h to 1h, civil time of Zikawei, etc. These numbers, reduced at first on the basis of 100 per hour, gave a mean, with reference to which the deviations or differences were taken, the latter being then smoothed by the method of the double mean. This work was done for the 31 years, 6 of which were of magnetic calm (1878, 1879, 1888, 1889, 1900 and 1901), and 6 of magnetic activity (1883, 1884, 1892, 1893, 1905 and 1906). Tables 1 and 2 and Fig. 1 represent these deviations.
Note concerning the measurement of ionic density on the top of a tower
Authors: Swann W. F. G.
Published: February 2008

On pages 35–37 of the March issue of the Journal for the current year, P. L. Mercanton gives some very interesting results of measurements of the atmospheric ionization made by him on a parapet near the top of a tower, and in the interior of the tower at its base. He finds that if n+ and n− refer, respectively, to the positive and negative ionic‐densities, n+/n− is much larger for the measurement made in the strong electric field near the top of the tower than in the zero electric field in the interior of its base. Thus, for n+/n− as measured at the top of the tower, values 4.33, 2.16, 4.46, and 1.70 were obtained on four different occasions, while the corresponding values for the foot of the tower were, respectively, 1.31, 1.09, 1.24, and 1.19.

I wish to call attention to the confirmation, afforded by these observations, of the view put forward in my former communication1 as to the effect of the charge induced on the Ebert ion‐counter by the potential‐gradient in modifying the values obtained in ionic‐density measurements. The theory of the phenomenon shows that, for a potential‐gradient of the normal sign, measurements of n+ should be unaffected by the induced charge, while those of n− should be too small. The effect of the negative induced charge on the instrument is to retard the velocity of the approaching negative ions. Thus, these ions move slower than the incoming stream of air, with a result that a smaller number of them enter the instrument per second than would enter if there were no induced charge. The positive ions are accelerated by the induced charge, but theory shows that the excess number of ions entering the instrument is just equal to the number which are captured by the outer cylinder of the apparatus, so that the measurements of n+ are unaffected by the induced charge.
Values of the magnetic elements at the Samoa Observatory
Authors: Angenheister G.
Published: February 2008

The values for the years 1909–1916 are preliminary ones; they may require slight corrections of a few tenths of a minute for declination and inclination, and a few gammas for the intensity components. The final values of I and Z for 1909 and 1910 must be deferred.

The tabular quantities are based upon “Stationstheodolit Tesdorpf 2025” and “Stationsinductor Schulze 2.” The values have not yet been referred to the International Magnetic Standards (I. M. S.), as determined from the extensive comparisons of the Department of Terrestrial Magnetism; the relations which may serve for the reductions to I. M. S. are given on next page.
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.
The radium content of sea‐salt specimens collected on cruise IV of the Carnegie
Authors: Hewlett C. W.
Published: February 2008

The following is an account of an investigation which was carried out in the laboratory of the Department of Terrestrial Magnetism at Washington to determine the amount of radium in some samples of sea salt collected by the Carnegie in the Atlantic and Pacific oceans, 1915–1917.1 The method of investigation was that first used by Joly and described by him in volume 32 of the Philosophical Magazine, 1911. The sea salt was mixed with two to three times its weight of a fusion mixture of sodium and potassium carbonates, and this mixture was heated to about 1,000°C. in an electric furnace. At this temperature carbon dioxide bubbled off from the mixture and presumably carried with it any radium emanation previously present in the mixture.
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.
Magnetic elements at Potsdam, 1918, and De Bilt, 1915–1917
Authors: Van Dijk G.
Published: February 2008

I beg to communicate herewith at the request of Prof. Schmidt in Potsdam the mean values of the magnetic elements at Potsdam for 1918 and at the same time the values at De Bilt for 1915‐1917.
The magnetic storm of August 11–12, 1919, as observed at the Watheroo Magnetic Observatory
Authors: Wallis W. F.
Published: February 2008

Our magnetograph has recently recorded a large magnetic storm which began at 6h 6m G.M.T., August 11. After some preliminary movements, lasting for 49 minutes, rapid oscillations of large amplitude began suddenly at 6h 55m. At 9h 25m of the same day these rapid oscillations gave place to long slow movements which continued until 16h 22m, when the rapid oscillations started again and continued until about 11h 0m on August 12. From this time on slow movements prevailed until the end.
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.
Solar‐constant values at Calama, Chile, March‐April, 1920
Authors: Abbot C. G.
Published: February 2008

[The following values of the solar constant observed at the Smithsonian Institution station, Calama, Chile, as communicated by Dr. Abbot, are of special interest in connection with the severe magnetic storm of March 22–23, and the marked solar activity of that period.1 It is very gratifying that Dr. Abbot has devised a method of observation and reduction which makes it possible to obtain a value of the solar constant within a few hours after the observations have been made and to receive the data at Washington as promptly as the mail service permits. The values from July, 1918, to January, 1920, inclusive, will be found in various issues of the Monthly Weather Review, January, 1919, to February, 1920. The values from January to March, 1920, Dr. Abbot states, “were all high—of the order of 1.96 to 2.00”. It will be observed from the. table that the lowest value (1.866) since January was observed on March 23—Ed.]
Magnetic observations at Rude Skov, May 29, 1919
Authors: Ryder Captain Carl
Published: February 2008

[The data supplied for Rude Skov Magnetic Observatory, Copenhagen, Denmark, consisted of values of magnetic declination (D), horizontal intensity (H) and vertical intensity (Z), for every minute from 9h 58m to 16h 32m, Greenwich civil mean time, May 29, 1919. Tables 1 and 2 contain the derived five‐minute means. Geographic coordinates: lat., 55° 50′ G. N.; long., 12° 27′ or 0h 49m .8E.—Ed.]
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.
Ueber die Bestimmung der erdmagnetischen Aktivitaet
Authors: Schmidt Von Adolf
Published: February 2008

Durch die auf der Innsbrucker Conferenz (1905) beschlossene Einführung der internationalen Charakterzahlen1 ist eine in praktischer Hinsicht recht befriedigende Lösung der Aufgabe erzielt worden, die von Tag zu Tag wechselnde Lebhaftigkeit der erdmagnetischen Vorgänge zahlenmässig zu kennzeichnen. Die Einfachheit und Anschaulichkeit des Verfahrens hat fast alle Magnetwarten der Erde zur Mitwirkung veranlasst (nur Uccle und Tokio haben sich dauernd ausgeschlossen), und die mustergültige Verarbeitung und Veröffentlichung des einlaufenden Stoffs durch das Niederländische Meteorologische Institut macht die Ergebnisse der wissenschaftlichen Verwertung schnell und allseitig zugänglich. Der einzige, natürlich von vornherein bewusst in den Kauf genommene Mangel des Verfahrens liegt in dem subjektiven Charakter der Stufenschätzung an den einzelnen Observatorien. Er verliert indessen durch die grosse Zahl der im Schlusswert vereinigten, von einander ganz unabhängigen Einzelwerte sehr an Bedeutung und ist eine notwendige Folge der Unbestimmtheit des Begriffs der Aktivität.
Earthquakes recorded at Watheroo Observatory, May, 1920
Authors: Kidson Edward
Published: February 2008

The following earthquakes were recorded on the magnetograph of the Watheroo Magnetic Observatory, Western Australia:
The auroral radiant from American observations of 1915–1920
Authors: Wylie Charles Clayton
Published: February 2008

Several auroral displays visible in recent years have shown well‐defined coronae in the United States and Southern Canada. When streamers shoot up simultaneously from nearly every part of the horizon, they appear to meet in a rude crown of light known as the corona. Many series of observations have been made on coronae in Northern Europe, but in our latitudes aurorae are rarely of sufficient magnitude to show this feature. The recent brilliant displays have, therefore, offered Americans exceptional opportunity to observe the position of the center of the corona, or radiant of the auroral streamers.
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.
The criterion of magnetic disturbance
Authors: Chree Charles
Published: February 2008

1. A primary desideratum is to arrive at a clear idea of exactly what it is we want to measure. If our object is simply to discriminate between the days of a single month, with a view to selecting for special purposes the five quietest or five most disturbed days of the month, it is very doubtful whether the existing scheme of international “character” figures can be improved on. Its simplicity and the small amount of labor it entails are great recommendations. The disadvantages it seems to me to possess are: 1. The significance of any particular “character” figure, e. g., 1.5, is variable: it connotes decidedly less disturbance in a quiet than in a disturbed year.
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.