bluuebunny/crossref_metadata_2025 huggingface dataset:
Paleomagnetic evidence for spatially distributed Post‐Miocene rotation of western Washington and Oregon
Authors: Sheriff Steven D.
Published: February 2008

Anomalous paleomagnetic directions have been determined for 17 sites in the Frenchmans Springs member of the Wanapum basalt formation, Columbia River basalt group. These sites are located in the Ginkgo flows from near Vantage, Washington, to Portland, Oregon, a distance of approximately 300 km. The average paleomagnetic direction for six of these sites, centered around Vantage is D = 147°, I = 41°, α95 = 4.5°. The expected Miocene field direction is D = 355°, I = 65°. At some localities there are two distinct Ginkgo flows, in direct stratigraphic succession, with statistically identical anomalous directions. Their anomalous paleomagnetic direction makes these flows a valuable marker horizon in the Columbia River basalt group. The nondipole field direction of the Ginkgo flows correlates well with available results from the Miocene Cape Foulweather basalts of Oregon. This correlation strongly supports the hypothesis that these coastal basalts of Oregon are the distal ends of Columbia Plateau derived basalt flows. The spatial distribution of these anomalous field directions suggests about 14° of clockwise rotation between Vantage and Portland. Combining these data with data from the Oregon Coast basalts allows a maximum declination difference of about 35°. The increase in declination can be best explained by clockwise rotation, about nearby vertical axes, increasing to the southwest across the Columbia Plateau and Oregon coast.
Uplift, faulting, seismicity, thermal spring and possible incipient volcanic activity in the Lesotho‐Natal Region, SE Africa: The Quathlamba Hotspot Hypothesis
Authors: Hartnady C. J. H.
Published: February 2008

Various features of the Lesotho‐Natal region of south‐eastern Africa, namely, its anomalously high topographic elevation, the occurrence of numerous thermal springs, a few enigmatic CO2 gas exhalation sites, and a significant level of current seismicity in certain zones, suggest that there is some neotectonic activity here. In 1983, there were also media reports of a small volcanic eruption in Lesotho. It has been suggested that a process of continental margin‐parallel warping was in operation during the Plio‐Pleistocene period to produce the apparent uplift and seaward tilting of older geomorphological land‐surfaces, but the fundamental geophysical cause of this process remained unclear. This “cymatogeny” or anorogenic plateau uplift has recently been related to absolute motion of the African continent over the former position of an oceanic spreading ridge but the hotspot reference frame was not used in the absolute motion modelling. As an alternative hypothesis for the Lesotho‐Natal phenomena, the existence of a mantle hotspot near 30°S, 29°E is invoked, its Cenozoic track is modelled, and the ages of a chain of volcanic seamounts in the Mozambique Basin are predicted. The results appear to confirm the self‐consistency of the hotspot frame as a preferred reference system for lithospheric absolute motion.
Appalachian carboniferous dextral strike‐slip faults: An example from Brookneal, Virginia
Authors: Gates A. E. , Simpson C. , Glover L.
Published: February 2008

The northern Appalachian, dextral fault system of late Paleozoic age is also present in the central and southern Appalachians. An example of a dextral strike‐slip fault is the 4 km wide Brookneal shear zone in the southwest Virginia Piedmont. The shear zone is, in part, superimposed on the Melrose Granite where an S‐C mylonite was produced by dynamic recrystallization of all constituent minerals. The Arvonia metasedimentary and Charlotte belt metavolcanic rocks contain spaced dextral shear bands at a consistent +24° ± 3° to the shear zone boundary. A minimum displacement estimate of 17 km was obtained from rotated foliation measurements in the Melrose Granite. The age of movement on the Brookneal shear zone has been constrained by isotopic dating to between 324 and 300 Ma. Other faults in the southern Appalachians, including the Nutbush Creek and Modoc zones show similar ages and relative offsets. Possible plate tectonic models that could account for the late Paleozoic dextral fault system throughout the Appalachians include: (1) tectonic escape resulting from the collision of a plate with North America to the north of the Canadian Appalachians, (2) postcollision interplate readjustments involving counterclockwise rotation of Africa relative to North America, and (3) oblique convergence of eastern North America with an oceanic plate moving west.
Fission track evidence for the source of accreted sandstones, Barbados
Authors: Baldwin Suzanne L. , Harrison T. Mark , Burke Kevin
Published: February 2008

A part of the accretionary wedge associated with the Lesser Antilles arc system is exposed in an area of approximately 50 km² in northeastern Barbados. Zircon separates from sandstones collected from the Scotland District, Barbados, W. I., were analyzed using the fission track technique in order to assess the spectrum of source areas from which these terrigenous sediments were derived and to better constrain the timing of deposition. Results yielded a mixture of ages with strong groupings from 25–80 Ma, 200–350 Ma, and greater than 500 Ma. The youngest population indicates that some of the Scotland beds, previously dated by paleontologic methods as Eocene, may actually be as young as late Oligocene. Possible source areas include the Lesser Antilles arc, the Netherlands‐Venezuelan Antilles arc, and the Caribbean Mountains of Venezuela. The 200–350 Ma population may reflect partially annealed cratonic material, an Andean component, and/or material associated with a Triassic rifting event. The oldest zircons (>500 Ma) and metamict zircons were likely derived from the South American craton. Detrital feldspars separated from sandstone at the base of Chalky Mount were analyzed by the 40Ar/39Ar age spectrum technique. Results yield what is interpreted to be a slow cooling gradient from 1350 Ma to 925 Ma and provides additional evidence of a cratonic source for the accreted sediments. Based on results from this study, and paleogeographical constraints, it is proposed that source areas for the Scotland sandstones of Barbados may have included the Guayana shield, Central Cordillera, uplifted areas of coastal South America, and the Lesser Antilles volcanic arc. We speculate that in Late Oligocene time an immense “proto‐Orinoco” river system flowed in a northeasterly direction from the shield through the northern Venezuelan mountain system (Cordillera de la Costa and Araya‐Paria) finally emerging into the Caribbean Sea in the area now occupied by Unare depression. Sediments comprising this deltaic complex and deep sea fan were either deposited directly into the trench or onto the sea floor where they were soon after caught up in the accretionary wedge of the Lesser Antilles arc system. This article contains supplementary material.
The Ouachita System in northern Mexico
Authors: Handschy James W. , Keller G. R. , Smith K. J.
Published: February 2008

The Ouachita system in northern Mexico can be subdivided into four unique tectonostratigraphic provinces: the foreland, the frontal zone, the interior zone, and the Coahuila terrane. Each province is defined by specific lithologic characteristics, structural styles, and regional Bouguer gravity anomalies. The Ouachita foreland is characterized by a carbonate dominated shelf which was disrupted during the late Paleozoic by several basement cored uplifts. The frontal zone is a northwest migrating foredeep and fold‐thrust belt; clastic sediments derived mainly from the fold‐thrust belt filled the foredeep and were subsequently deformed as the fold‐thrust belt migrated. The interior zone is the metamorphic core of the migrating fold‐thrust belt and is characterized by a distinctive positive Bouguer gravity anomaly. The Coahuila terrane is a composite terrane which includes a late Paleozoic volcanic arc and a piece of exotic continental crust which was probably afixed to North America during the final stages of the Ouachita orogeny and then left behind during the opening of the Gulf of Mexico.
Tectonic wedges and offset Laramide structures along the Polochic Fault of Guatemala and Chiapas, Mexico: Reaffirmation of large Neogene displacement
Authors: Burkart Burke , Deaton B. C. , Dengo Carlos , Moreno Guillermo
Published: February 2008

Fault wedges along the Polochic fault of northern Guatemala and Chiapas, Mexico record left‐lateral slip of from 20 to 65 km that accompanied documented Neogene slip of 130 km across this North American—Caribbean plate boundary fault. Wedges can be correlated to source areas consistent with left‐lateral displacement along the Polochic fault. They occur adjacent to restraining bends in three areas where changes in strike of the fault have been mapped. These wedges, which have been previously interpreted as allochthons emplaced along low‐angle reverse faults, are bounded by high‐angle faults. Folds that terminate against the Polochic fault are part of a regional fold belt that originated during the Campanian through Paleocene (Laramide) orogenic event. A previous contention that some of these major folds are secondary and related to fault movement is shown to be incorrect. The 130 km model of left‐lateral offset across the Polochic fault is reviewed along with evidence for and against a Neogene time of major displacement. Additional evidence for the model is presented: (1) Late Cretaceous granitoid rocks from near Motozintla, Chiapas, Mexico (northern fault block), are correlated with granitic rocks of the Santa Maria Batholith in the region of Huehuetenango, Guatemala (southern block), (2) mineralization at the contacts of the granitoid intrusives of the two areas is correlated, (3) points of deflection of Laramide structural axes are correlated across the fault, (4) a major thrust sheet similar to that of the Sierra de Santa Cruz in eastern Guatemala is reassembled by reversing 130 km of left‐lateral slip which has offset serpentinites north of the fault in western Guatemala and those south of the fault in central Guatemala.
Stress orientations from well bore breakouts in the Coalinga Region
Authors: Springer James E.
Published: February 2008

Borehole breakouts are caused by unequal stress concentrations around a borehole resulting in shear failure of the borehole wall and creating hole elongation perpendicular to the maximum horizontal in situ stress. Breakouts in Tertiary sedimentary rocks were identified in 10 holes in the West Coalinga, Cantua Creek, and West Haven oil fields in the western San Joaquin Valley. The deeper and more reliable (1.5 to 3.7 km) breakouts were oriented northwest, indicating northeast compressive stress, perpendicular to the major fold axes in the San Joaquin Valley and at a 70°–90° angle to the major strike‐slip faults in the Coast Ranges. This stress direction is consistent with a reverse slip component on northwest‐trending faults in the region and with the focal mechanisms reported for the May 1983 Coalinga earthquake. The existing literature on stress measurements in central and southern California indicates that on a regional scale, the stress regime is transitional between thrust and strike‐slip faulting. A hydraulic fracture test in the Kettleman Hills oil field at 3 km depth indicates that this stress regime exists in the upper crust near Coalinga as well.
Thrusting of the Hindu Kush over the Southeastern Tadjik Basin, Afghanistan: Evidence from two large earthquakes
Authors: Abers Geoffrey , Bryan Carol , Roecker Steven , McCaffrey Robert
Published: February 2008

We infer from the mechanisms and depths of two large earthquakes that the Hindu Kush is actively thrusting northwest over the Tadjik basin and that the basin is closing rather than being displaced to the west. Teleseismic body waves were used to determine focal mechanisms and depths for the two largest shallow earthquakes on the southern edge of the basin. The two earthquakes, on June 24, 1972 (mb=6.0), and December 16, 1982 (mb=6.2), have seismic moments of 2 × 1018 N‐m and 6 × 1018 N‐m, respectively. Focal mechanisms of both events indicate almost pure thrust faulting with nodal planes striking northeast‐southwest. The inferred fault planes dip southeast, at 20° for the first event and 50° for the second. The P axes for both events are oblique to the direction of relative motion between India and Asia, suggesting that the Pamir is overthrusting the basin to the west. Depths for both earthquakes are between 20 and 25 km and place them well below the Tadjik basin sediments. The depths and steep fault planes suggest that these earthquakes represent a downdip extension within the basement of shallow folding and thrusting seen in the sediments northwest of the events. Thus convergence in Afghanistan between India and Eurasia is taken up along southeast dipping thrust faults north of the Hindu Kush as well as by northward subduction under the southern part of the range.
Early Mesozoic rift basins of eastern North America and their gravity anomalies: The role of detachments during extension
Authors: Bell Robin E. , Karner Garry D. , Steckler Michael S.
Published: February 2008

Two end‐member models of extension involving detachments have been developed. One model incorporates a fault that soles at mid‐crustal level overlying a broad region of pure shear in the lower crust. The second, referred to as the simple shear model, includes a detachment continuing through the entire crust and terminating in a region of concentrated extension in the lower crust. Both models predict basins with no localized thermal effect. With the inclusion of flexural isostasy, both models predict footwall uplift whose amplitude and wavelength are controlled by the detachment geometry and the lithospheric strength. A gravity anomaly over the hanging wall block distinguishes the simple shear model from the intracrustal detachment model. The early Mesozoic basins of the eastern North America, believed to have formed as the result of the normal‐slip reactivation of a Paleozoic thrust system as the Atlantic opened, are associated with distinctive hanging wall gravity highs. These gravity highs, the basin geometry, the lack of a thermal subsidence phase in the rift basins, and the presence of a highly extended and heated region to the east, suggest that the simple shear model may be applied. The simple shear model fits the outer hanging wall anomaly and permits a region of lower crustal extension to be mapped. These basins contain an abundance of basalt flows and diabase sills despite the lack of evidence for regional heating or thermal subsidence, implying that a source, external to the basin, must exist for this magmatic material. The detachment fault may facilitate the movement of the molten mafic material into the rift basins from an offshore region of greater heating and extension. The addition of 2 km of mafic material along the model detachment accounts for the observed inner gravity high and the lack of a negative gravity anomaly across these basins. The match of this modified simple shear model to the observed gravity suggests that the region of greater extension seaward of the hinge zone is the source for the widespread dikes and sills within the basins and the coastal plain and helps explain the geochemical homogeneity of these intrusives and extrusives along 2000 km of the eastern seaboard.
Episodic tectonic subsidence of Late Holocene salt marshes, northern Oregon Central Cascadia Margin
Authors: Darienzo Mark E. , Peterson Curt D.
Published: February 2008

Salt marsh subsurface deposits (0–4 m depth) in Netarts Bay, a small coastal lagoon of northern Oregon, record six events of marsh burial in the last several thousand years. Five of the buried marsh surfaces show sharp, nonerosional upper contacts with either anomalous sand layers (tsunami deposits) or tidal flat mud deposits. These sequences indicate episodic, abrupt subsidence of the marsh surfaces to low intertidal levels. In contrast, lower marsh contacts with underlying intertidal muds are gradational, indicating gradual uplift and development of the marsh. Three independent measures of deposit elevation relative to mean tidal level (percent organics, diatom assemblages, and percent eolian sand) have been used to estimate vertical displacements of marsh surfaces. Abrupt subsidence displacements of 1–1.5 m alternate with gradual uplift displacements of the order of 0.5–1.0 m. The vertical tectonic movements are interpreted to reflect coseismic strain release (abrupt subsidence) following interseismic strain accumulation (gradual uplift), associated with interplate coupling between the Juan de Fuca Plate and the North American plate in the Cascadia subduction zone. Recurrence intervals between subsidence events range from possibly less than 300 years to at least 1000 years, with the last dated event likely occurring 300–400 radiocarbon years before present (RCYBP). Significant 14C age overlaps of at least four subsidence events recorded at Netarts and reported for southern Washington and other northern Oregon bays (at 300–500, 1000–1300, 1400–1800, and 3000–3300 RCYBP) suggest the potential for event synchroneity over at least 200 km of the central part of the Cascadia subduction zone. Additional work is needed to test the synchroneity of these episodic events of coseismic subsidence.
Seismicity and tectonic deformation rate in Soviet Armenia: Implications for local earthquake hazard and evolution of adjacent regions
Authors: Westaway Rob
Published: February 2008

The Spitak, Armenia, earthquake of December 7, 1988 (Ms 6.7; Mo∼10×1018 Nm), was the largest this century in Soviet Transcaucasia, in the northern part of the zone where the Arabian and Eurasian plates converge at ∼30 mm yr−1. Field observations in its epicentral area and information from historical and recent earthquakes in and around Armenia are used to determine shortening rates and hence to investigate how shortening is partitioned between the Great Caucasus, Armenia and other parts of Soviet Transcaucasia, and eastern Turkey and NW Iran farther south. This earthquake produced more than 20 km of surface faulting with up to 1.5 m reverse slip and 0.4 m right‐lateral slip on a fault with WNW strike and southward slip vector azimuth. Much of the local topography has formed by slip on faults with similar orientation. There is no evidence of substantial recent folding elsewhere in Armenia, suggesting that shortening in Armenia occurs mainly by slip on these faults. Shortening rate across Armenia is ∼1 mm yr−1 at strain rate ∼2 × 10−16 s−1. With likely slip rate on each fault ∼0.2 mm yr−1, the local topography has formed in ∼1 Myr. Shortening rate in the eastern Great Caucasus farther north can be estimated using Quaternary uplift rate, assuming uplift is caused by crustal thickening and occurs in isostatic equilibrium. Although Quaternary uplift rates from 0.05 to ∼10 mm yr−1 have been previously suggested, any rate above ∼1 mm yr−1 is too rapid to be explained by this process. The remaining rates range from 0.05 to 0.2 mm yr−1 and imply ∼1 to 5 mm yr−1 local shortening rate, suggesting overall shortening rate across the Soviet part of the convergent zone is only ∼2 to 6 mm yr−1. Historical seismicity suggests that at least ∼1 mm yr−1 of this shortening is coseismic. Most of the convergence between Arabia and Eurasia is thus taken up at present farther south in eastern Turkey and NW Iran along with probable substantial westward expulsion of crustal material, and most of the topography and crustal thickness in the Great Caucasus probably already existed at least 10 Myr ago.
Tertiary extension and contraction of lower‐plate rocks in the Central Mojave Metamorphic Core Complex, southern California
Authors: Bartley John M. , Fletcher John M. , Glazner Allen F.
Published: February 2008

Several authors recently have proposed the “rolling‐hinge” model for the formation of extensional detachment faults in metamorphic core complexes. In this model, isostatic uplift of the denuded footwall of a major normal fault causes the near‐surface part of the fault to rotate from a higher to a lower dip. For the rolling‐hinge model to be acceptable, the footwalls of detachment faults must have undergone the strain pattern dictated by the rolling hinge. In this paper, the structural development of the footwall of the central Mojave metamorphic core complex is used as a field test. Tertiary structures in the lower plate of the core complex record NE‐directed ductile extensional shear followed by cataclastic NE‐side up shear with a significant component of contraction along the previous extension direction. This strain history agrees with the rolling‐hinge model, and particularly with a version of the model in which footwall uplift occurs by a combination of elastic flexure and flexurally driven upper‐crustal failure. Similar late‐stage layer‐parallel contraction appears to be present in some other tectonically denuded terranes of the Basin and Range, suggesting that the flexural‐failure rolling‐hinge model for extensional terranes may be widely applicable.
The magnetic work of the United States coast and geodetic survey
Authors: Bauer L. A.
Published: February 2008

In the “Plan for the Reorganization of the Survey of the Coast, as adopted by a Board convened on the 30th of March, 1843, by direction of the President of the United States,” explicit provision is made for the making of “ all such magnetic observations as circumstances and the state of the annual appropriations may allow.” Since then Congress, by more or less generous appropriations, has distinctly recognized the importance of this feature of the work of the Survey.

Under the first Superintendent, Professor F. R. Hassler, the magnetic declination (“variation”) was supplied, on the Coast Survey Charts, as determined with the aid of the ordinary nautical instrumental means then in vogue. In the Transactions of the American Philosophical Society, Philadelphia, 1825, Professor Hassler proposed to measure relative magnetic intensity by means of oscillations of a needle, no method for absolute measurement being then known.
The magnetic anomaly near Kursk, Russia
Authors: Littlehales G. W.
Published: February 2008

The Imperial Russian Geographical Society of St. Petersburg having invited French geomagneticians to examine the distribution of the terrestrial magnetic elements in the Province of Kursk in Russia, where strikingly abnormal values of the declination, inclination, and intensity had previously arrested the attention of Russian scientists, the Minister of Public Instruction of France selected Prof. Moureaux to make a magnetic survey of that region. The Province of Kursk is situated between the parallels of 50° 20′ and 52° 20′ north latitude, and the meridians of 31° and 36° of longitude east of Paris. Prof. Moureaux set out from Paris on May 11, 1896, and, stopping at Pawlowsk to compare the instruments that were destined for use in the magnetic survey with those of the Russian magnetic observatory, in order to relate his observations to the past and future observations of the Russian investigators in the same region, arrived at Kursk on May 21st. Here he established a self‐recording magnetograph in a specially constructed subterranean apartment, and thus provided himself with the means of reducing to a common epoch the values that he subsequently observed in the field with the same portable magnetic instruments which had already been used in the determination of the magnetic elements in France and Algeria, and which are described in the Annales du Bureau Central Météorologique de France, 1884 and 1896.
Über die Errichtung stationärer und temporärer magnetischer Observatorien
Authors: Eschenhagen Von M.
Published: February 2008

Die erdmagnetische Forschung bedarf wie bekannt für die Aufstellung ihrer subtilen Apparate besonders sorgfältig errichteter Gebäude, um einestheils vor dem Einflüsse benachbarter Eisenmassen gesichert zu sein, andererseits um die zur Erzielung präciser Messungen nöthige Constanz der Temperatur zu erreichen. Man hat derartige Anlagen häufig mit ändern Instituten, Sternwarten oder meteorologischen Observatorien verbunden, vorwiegend wohl aus äusseren praktischen Gründen.

Ursprünglich war der Astronom der Beobachter fast aller Naturerscheinungen, wozu ihn die Aufmerksamkeit, die er dem gestirnten Himmel widmete, sowie die Präcision, mit der er seine Beobachtungen der Rechnung zu unterwerfen wusste, besonders anregte und befähigte. Mit dem Ausbau der wissenschaftlichen Behandlung der einzelnen Gruppen von Phänomenen löste sich ein Zweig nach dem ändern von der eigentlichen theoretischen und praktischen Astronomie ab. So trennten sich Meteorologie und Geodäsie, als sich deren Gebiete specialisirten, und die Einführung des physikalischen Experimentes führte zur Begründung des neuesten Zweiges, der Astrophysik. Ob man den Erdmagnetismus zu einem der soeben genannten Gebiete hinzuschlagen will oder ob man ihn selbst‐ständig ausbauen will, dürfte, wie bereits bemerkt, meistens nach äusseren, praktischen Gesichtspunkten entschieden werden; vom wissenschaftlichen Standpunkt aus ist sicher, dass die Besonderheit der magnetischen Beobachtungs‐ und Mess‐Methoden ihm seinen eigenen Weg weisen. Dieser Umstand dürfte genügen, für die innere Berechtigung des Erdmagnetismus als selbständige Wissenschaft ausschlaggebend zu sein, da die Beobachtungen das Fundament für seine Fortentwickelung bilden. Der Umstand, dass eine Verknüpfung der Ergebnisse mit einem der oben genannten oder anderen Forschungs‐Zweigen stattfindet, kann nicht wohl Anlass sein, ihn zu einem oder dem anderen hinzu zu rechnen, da man ihn sonst bald zur Astrophysik, wenn man seine Verwandtschaft mit den Erscheinungen auf der Sonnenoberfläche in Betracht zieht, bald zur Meteorologie, wenn man die Vorgänge in den höchsten Regionen der Atmosphäre studirt, rechnen müsste. In letzer Instanz müssen alle Wissenschaften convergiren, welche als gemeinsames Studienobject die kosmisch‐physikalische Stellung unserer Erde haben, und es können daher die vergleichenden Folgerungen von jedem dazu befähigten Gelehrten gezogen werden, wenn er auch die Einzelheiten der Beobachtungsmethoden nicht beherrscht. Zur Entwicklung jedes einzelnen Zweiges aber gehören Observatorien, in welchen die entsprechenden Methoden in ihrer Eigenart am besten gefördert werden können.
On glass windows in magnetometers
Authors: Chree Charles , Watson W.
Published: February 2008

I have read with interest the note by Dr. Morize on pp. 29, 30, of the last number of the Journal, with your note thereon. I understand Dr. Morize to mean that when a ray of light is transmitted through both the windows of his magnet‐box there is a refraction error of 7″ 11′, but that he is uncertain whether this arises wholly from one window or partly from each. He explains, however, that refractive error from the window nearest the telescope would not matter, so far as the declination is concerned, supposing use made as usual of a distant mark.

It is easy to hold the magnet box in such a position that the line of vision of the telescope, directed to the distant mark, cuts the center of either window (of course at an angle) and passes through an open side. In this way, by interposing and removing the box, each window can be tested separately, without taking the box to pieces. A second method is to fix a piece of looking‐glass on an independent support inside the magnet‐box, and view the image of the wire in a telescope reflected by this with the box away and in situ. The second method allows of normal incidence of the light ; the first if less accurate is simpler, and it easily shows whether there is a refraction error of the order of 10′. Magnetometer verniers usually show only 20′, so that quantities less than 10′, need hardly be considered.
Bemerkung zu der Mittheilung des Herrn Moureaux “sur la périodicité des perturbations de l'aiguille aimantee horizontale, à l'Observatoire du Parc St. Maur”
Authors: Von G. Lüdeling
Published: February 2008

In der oben genannten Mittheilung findet Herr Moureaux bezüglich des täglichen Ganges der magnetischen Störungen, dass bei der Declination ein Maximum um etwa 1h a. m.; ein Minimum in den Morgenstunden von 5–8 Uhr erreicht wird. Bei den Störungen der Horizontal‐Intensität ist der tägliche Gang ein ganz anderer, hier fällt das Maximum auf die Mittagstunden, das Minimum auf ungefähr 5h a. m.

Diese Resultate stehen nun mit früheren, von anderen Forschern gefundenen nicht ganz im Einklang.
The magnetic work of the Norwegian North Polar Expedition, 1893–96
Authors: Hazard D. L.
Published: February 2008

A perusal of Nansen's “Farthest North” shows clearly that the Norwegian North Polar Expedition of 1893–96 was not simply an attempt to reach the North Pole, but a carefully planned scientific expedition, prepared to avail itself of every opportunity to extend our knowledge in every branch of science. It requires a study of the Scientific Results, however, to appreciate fully the immense amount of scientific work done by the small band of men on board the Fram.

The fundamental idea of the expedition, allowing the ship to become fast in the ice and drift with it across the Polar Sea, gave to the members of the party abundant time for making the various scientific observations and investigations for which provision was made in planning the work. Moreover, astronomic and magnetic observations could be made with nearly the same accuracy on the ice as on land, provided the time occupied was not too long, and no sudden disturbance of the ice floe took place. Yet, it could not be assumed that the absolute position of the ship changed with any regularity, nor that the relative position of different parts of the ice floe was the same from day to day.
The proposed magnetic researches of the Norwegian polar stations in 1902–1903
Authors: Birkeland Kr.
Published: February 2008

As leader of the expedition started by the Norwegian government for the study of Earth‐magnetism, Boreal Lights, and Cirrus‐clouds, I beg to state that during the time from August 1, 1902, until June 30, 1903, four Norwegian Stations will be erected, viz.: at Bossekop (Finmarken), at Dyrafjord (Iceland), at Aksel‐Island (Spitzbergen), and Matotschkin‐Schar (Novaja‐Zemlja).

At these four stations the three magnetic elements will be registered photographically. To this effect registering instruments will be employed like those used by the contemporary Antarctic Expeditions. The three elements will also be determined absolutely. The term observations stipulated by the Antarctic Expedition will also be carried through at these stations.
Letter to editor: Mr. Watson's comparison at Kew Observatory
Authors: Chree C.
Published: February 2008

With reference to the note (Vol. 7, p. 99) on the abstract of Mr. Watson's paper in the “R. S. Proceedings,” and to the foot‐note attached thereto, I would point out that, subsequent to the publication of the abstract, Mr. Watson found that, “owing to a mistake in the corrections applied to the weights used in the silver depositions, the numbers . . . which appeared in the ‘Proceedings of the Royal Society’ (Vol. 69, p. 1) require correction.” This correction (see “Phil. Trans.,” Vol. 198 A, pp. 454‐6) raises Mr. Watson's values dependent on the weights in question by some 6 γ or 7 γ, bringing his mean value for H, expressed in international units, into almost exact agreement with the corresponding mean from the Kew magnetometer. Mr. Watson himself (1. c., pp. 461–2) considers .0011183 a more probable value for the electrochemical equivalent of silver than the value .001118 accepted at present, and if the revised value he approves were accepted, it would increase the apparent difference between the results from the coil and magnetometer. It is hardly necessary to point out that until the electro‐chemical equivalent of silver is really known to 5 significant figures—instead of to 4, as at present—any comparison of coils and magnetometers based on it can not lead to absolute final results.
Scientific work of the Ziegler Polar Expedition
Authors: Peters Willliam J.
Published: February 2008

The Ziegler Polar Expedition, which left Norway, July 10, 1903, was not intended to be a scientific expedition. Only such scientific work was contemplated as would further the ends of the expedition and also such as could be done without detriment or delay.

Meteorological observations were begun immediately after leaving Norway and continued without interruption to the date of the return, July 28, 1905. These observations were made and recorded according to the methods of the United States Weather Bureau.
Luftelektrische Beobachtungen WÄhrend der totalen Sonnenfinsternis 1905 August 30 in Palma de Mallorca
Authors: Ebert H.
Published: February 2008

Auf die Bedeutung elektrischer Beobachtungen während einer totalen Sonnenfinsternis haben in dieser Zeitschrift vor kurzem die Herren J. Elster und H. Geitel hingewiesen (S. 17; vergl. auch L. A. Bauer ebenda S. 21). Die erst Genannten haben selbst,—unterstützt durch Mittel des Department Terrestrial Magnetism der Carnegie Institution,—eine grössere Anzahl diesbezüglicher Messungen in Palma de Mallorca angestellt, über die sie an geeigneter Stelle berichten werden. Ich habe am gleichen Orte am Tage der Verfinsterung eine Reihe von Ionenzählungen vorgenommen mit dem von mir construierten Aspirationsapparate und zwar mit der zuletzt beschriebenen Form (Verhandl. d. Deutschen Phys. Ges. 7, 35, 1905) mit vertikal stehendem Saugrohre, welche von der Windrichtung unabhängige Werte liefert.
Luftelektrische und Photometrische beobachtungen während der totalen Sonnenfinsternis vom 30. August 1905, in Palma (Mallorca)
Authors: Elster J. , Geitel H. , Harms F.
Published: February 2008

Im folgenden erlauben wir uns, dem “Department Terrestrial Magnetism” der “Carnegie Institution of Washington” einen Bericht vorzulegen über die Ausführung des von uns übernommenen Auftrages, während der Sonnenfinsternis vom 30. August dieses Jahres Beobachtungen über die elektrischen Eigenschaften der Atmosphäre innerhalb der Totalitätszone anzustellen.
Cheltenham Magnetic Observatory registration of effects from electric cars over twelve miles or twenty kilometers distant
Authors: Bauer L. A.
Published: February 2008

A close inspection of the magnetograms obtained during the past year at the United States Coast and Geodetic Survey Magnetic Observatory situated at Cheltenham, Maryland, employing the sensitive Eschenhagen‐Edler variometers, has disclosed the interesting fact that magnetic effects are being photographically registered daily which are to be ascribed to certain electric car lines in the vicinity of the City of Washington.

The Observatory is situated about 14 miles or 22 ½ kilometers, in an air line, southeast from the United States Capitol at Washington, in a rural region, far removed from possible disturbing effects of industrial plants. The selection of the site of the Observatory was made only after a careful examination of the possible sites fulfilling the requirements of a principal or standard observatory for the purposes of the magnetic survey work of the United States Coast and Geodetic Survey. This particular locality offered, for various reasons, the least inducement for the penetration of electric car lines. Nor have electric car lines thus far entered this region. There is a possibility, however, that within another two years an electric car line may be constructed which will come within 3 or 5 miles (5–8 kilometers) of the Observatory.
Magnetic survey of the Dutch East Indies
Authors: van Bemmelen W.
Published: February 2008

In 1906 the survey was for the greater part completed by the observations secured on two trips, the first in the month of February from Pontianak up the river Kapuas to Central Borneo, the second along the Minor Sunda islands to Southern New Guinea. The instruments and methods of observation were the same as in previous years. The results given in the following table have not been corrected, either for instrumental difference with the standard instruments at Batavia, or for diurnal and other variations.
Porto Rico Magnetic Observatory, Vieques Island
Authors: Faris R. L.
Published: February 2008

The Porto Rico Magnetic Observatory of the United States Coast and Geodetic Survey, temporarily established in February, 1903, in the basement rooms of the old abandoned Spanish fort (Isabel) at Vieques, on the Island of Vieques, Porto Rico, was removed to a new site during the first part of April, 1907. The occasion for the change in the location of the observatory was that the Insular Government required the entire fort for the installation of a public hospital.

After a thorough examination and lnagnetic survey of the possible locations in the vicinity, a suitable site was found about ⅝ mile west of the old observatory (Fort Isabel). The erection of the special buildings required was begun the first of February, 1907, the work was completed under the supervision of Mr. W. B. Keeling (the present observer‐in‐charge), the variation instruments were installed, and records were being obtained on the 10th of April, 1907.
Atmospheric electricity observations at Battle Harbor, Labrador, during the solar eclipse of August 30, 1905
Authors: Burbank J. E.
Published: February 2008

The eclipse party sent to Battle Harbor, Labrador, by the Department of Terrestrial Magnetism of the Carnegie Institution of Washington, in addition to observations of terrestrial magnetism embraced in its program such observations of atmospheric electricity as could be obtained without interfering with its principal work. The time available for this work being thus limited it was decided to observe only potential gradient and specific conductivity. These observations were entrusted to Messrs. Bowen and Homrighaus, members of the party, and it is greatly to their credit that so much was accomplished under the particularly difficult and trying conditions encountered.
Biographical sketch of Wilhelm Weber Eduard
Authors: Dorsey N. E.
Published: February 2008

Wilhelm Eduard Weber was born at Wittenberg, October 24, 1804. He was the fifth of seven children. His father, Michael Weber, was Professor of Theology at the University of Wittenberg; this institution was united to the University at Halle in 1815, and the family then moved to the latter place. Of Wilhelm's early youth we know but little.
Results of magnetic observations made by the United States Coast and Geodetic Survey at the time of the total solar eclipse of August 30, 1905
Authors: Tittmann O. H.
Published: February 2008

In response to the request for co‐operation issued by the Director of the Department of Research in Terrestrial Magnetism of the Carnegie Institution of Washington, arrangements were made by the Coast and Geodetic Survey for special declination observations at the time of the total solar eclipse of August 30, 1905, at the five magnetic observatories of the Bureau and by the various magnetic observers engaged in field work. In accordance with the instructions issued, eye‐readings of the declination were made every minute from 5h to 11h a.m., 75th meridian mean time, and the temperature was read every fifteen minutes. The observers in charge of the various observatories were also instructed to take special care to have the self‐recording instruments in good adjustment. In addition, at Cheltenham, the Eschenhagen magnetograph was run on the “two hour” rate from 4h 30m to 6h1 30m a.m.
Regarding the magnetic effects of the total solar eclipse of August 30, 1905
Authors: Nordmann Ch.
Published: February 2008

I am pleased that Mr. Chree's remarks on the subject of my article in this Journal (March, 1907) afford me the opportunity of returning to this interesting question, and I beg to make the following observations:

1. In the table on p. 20 (loc. cil.) I give for various stations the differences at each instant observed between the force which at each station tends to draw the needle to the east and the value of this same force at Philippeville. I give the values of the forces in terms of 0.1 of my unit which is equal to 0.14γ. Mr. Chree assumes that I guarantee the exactness of these values to the nearest 0.1 of this unit; one will find nowhere in my article any such contention. I have measured, as is usual, the ordinates of the various curves of declination to the nearest 0.1 mm., next, as I have indicated (loc. cit. p. 19), and in order to make all of the curves comparable one with the other, I have multiplied respectively the ordinates by the proper factors in such manner, if I may thus express myself, “as to reduce them to the same horizontal component”. Now these factors reduced for the times from the values of H for the different stations and from the angular values of the curves in millimeters are none of them integral numbers, but fractional. I have thus naturally given the values of the table in question to the nearest 0.1 of my unit; as it is always the custom in like cases, I have not felt authorized to drop the last decimal which results from the measures and calculations for the different times for fear of introducing new errors.
On the distribution of magnetism over the Earth's surface
Authors: Passalskij Paul T.
Published: February 2008

[In order to make accessible Passalskij's memorable treatise1 to the readers of the Journal, who are unfamiliar with the Russian language, Prof. Paul Wernicke, working under the auspices of the Department of Terrestrial Magnetism of the Carnegie Institution of Washington, has translated the portions of chief interest, the first installment of which is given in the present number. For a biographical sketch of the author and a brief résumé of the contents of Passalskij's work, see Professor Leyst's article, this Journal, Vol. VII, pp. 67–74. The author during his all‐too brief life, he having died November 25, 1900, at the age of twenty‐nine years, evinced unusual talents, a tireless industry and an unbounded enthusiasm for magnetic work.—ED.]
Note on the magnetic effect of winds
Authors: Humphreys W. J.
Published: February 2008

It is known that lightning discharges produce temporary disturbances of the Earth's magnetic field in their neighborhood, often of magnitude sufficient to produce departures of several millimeters on the records, but no disturbances have been detected that could certainly be traced to the movements of charged clouds.

However, since a moving charge is an electric current, it follows that charged clouds as they drift by, and ionized winds with an excess of either positive or negative electrons, must produce magnetic fields, at right angles to their line of motion, whose disturbance of the Earth's field depends upon the direction and the speed of the winds, and upon the kind and extent of their electrification.
On the probable existence of a magnetic field in sun‐spots
Authors: Hale George E.
Published: February 2008

The lines in the spectra of Sun‐spots differ from those of the ordinary solar spectrum mainly through changes of intensity and width. Most of the spot lines are more or less widened, some of them are double, and a few are triple. These characteristics of the lines, and the fact that the revolution of electrically charged particles in a solar vortex might be expected to produce a magnetic field, led to a search for evidences of the Zee man effect in Sun‐spot spectra.

Light from a spot was passed through a Fresnel rhomb and Nicol prism, mounted before the slit of a spectrograph of 30 feet focal length, used in conjunction with the tower telescope of the Mount Wilson Solar Observatory. Photographs of the spectra were made in the third order of a Rowland grating, having 14438 lines to the inch. It was found that the relative intensities of the components of the double lines in the spot are reversed by rotating the Nicol through an angle of 90°. The widened lines are also shifted when the Nicol is rotated. Just such changes are observed if the same doublets are examined under the same conditions along the lines of force of a powerful magnetic field.
On the apparent alterations of mass disclosed by weighings of magnets
Authors: Bauer L. A.
Published: February 2008

I am of course very much interested in Dr. Lloyd's communication in this issue of the Journal. As he states, the question investigated was one which arose incidentally in the course of my investigation as to the limits within which we may assume a strict coupling of the Earth's magnetic forces. The following paragraphs are quoted from p. 33 of my paper, which as stated in the title was a “Preliminary Report:”

“In the course of this investigation I was led to make some experiments with regard to the first question which concerned Norman—whether magnetization altered the weight, or say mass, of a magnetizable substance. As I have not had the leisure to bring the experiments to a conclusion on this point, the present results should be regarded merely as preliminary to a more serious undertaking. They are herewith given primarily with a view of inciting experimentation on the part of others. I shall be greatly obliged if any one will bring to my attention any past experiments on this point other than those of Norman, as also any future experiments.”
Magnetic charts of the island of Sardinia
Authors: Palazzo L.
Published: February 2008

Several years ago I had the honor of presenting to the readers of Terrestrial Magnetism the magnetic chart of Sicily. I now venture to believe that some magnetic charts of the second in importance among the large Italian islands, Sardinia, would not be out of place in this Journal, especially as Sardinia reveals even more pronounced and characteristic magnetic features than Sicily.

The values of the magnetic elements which I have utilized for the construction of the charts, are essentially those which I determined since 1892, during a journey through the Island, by commission of the Direction of the Italian Central Meteorological Office. At a former date, viz., in 1884, magnetic measurements had been carried out at a few points of Sardinia, by Prof. Chistoni, my predecessor in the Meteorological Office. But since Chistoni's station‐points were considered insufficient for the tracing of magnetic lines, it was decided to resume observations in 1892. I have re‐occupied nearly all the points selected by him, and besides have added numerous new points to the chart. Within the same locality, I have frequently made measurements at two different points distant from each other a few kilometers or fractions of kilometer, with the object of bringing to a more satisfactory solution some doubts which had arisen concerning the existence of magnetic local disturbances.
Magnetische Beobachtungen in Seddin während des Kometendurchgangs, 19. Mai, 1910
Authors: Nippoldt Von A.
Published: February 2008

Gestatten Sie mir, mitzuteilen, dass wir im Observatorium zu Seddin, von Mai 16, 0h a.m. M. Gr. Z., bis Mai 21, Mitternacht, 8‐stündig, schnell laufend die Komponenten X, Y, Z registriert haben. Die Emptindlichkeit betrug bei allen dreien 2 γ auf den mm. Von Mai 20, 5h a. m. bis 1h p. m. und Mai 21, 1h p.m. bis Mn war der Lichtpunkt für Z unwirksam geworden; es bot Z aber in dieser Zeit, wie Potsdam zeigt, nichts von besonderem Interesse. Irgendein eigentümliches, nur bei schneller Registrierung erkennbares Phaenomen, das für einen Kometeneinfluss spräche, lassen die Kurven nicht erkennen.
Co‐operation in British Antarctic Expedition, 1910
Authors: Larmor J.
Published: February 2008

With reference to the above, I have to inform you that Dr. Simpson, who is accompanying this Expedition in charge of the Magnetic Observations, is willing to carry out a program of quick run observations as suggested in Dr. Chree's scheme below and the Royal Society would be very glad to secure the co‐operation of all observatories in its working. The observations secured will be destined for use in a complete discussion. The scheme is as follows:Proposed Term Hours.Two hours consecutive quick run at following dates and hours G.M.T. 0h 0m a.m. = Greenwich midnight.Runs from 8 a.m. to 10 a.m. G.M.T. on
Runs from 5 p.m. to 7 p.m. G.M.T. on
Runs from 6 p.m. to 8 p.m. G.M.T. on
Reasons for form the Scheme takes.