scholarly journals I. Notices of some conclusions derived from the photographic records of the Kew declinometer, in the years 1858,1859, 1860, and 1861

1862 ◽  
Vol 11 ◽  
pp. 585-590
Keyword(s):  
Relative Frequency ◽  
Magnetic Force ◽  
Total Force ◽  
Magnetic Disturbances ◽  
Different Parts ◽  
Made In ◽  
Photographic Records

The discussion of the magnetic observations which have been made in different parts of the globe may now be considered to have established the three following important conclusions in regard to the magnetic disturbances: viz., 1. That these phenomena, whether of the declination, inclination, or total force, are subject in their mean effects to periodical laws, which determine their relative frequency and amount at different hours of the day and night. 2. That the disturbances which occasion westerly and those which occasion easterly deflections of the compass-needle, those which increase and those which decrease the inclination, and those which increase and those which decrease the magnetic force have all distinct and generally different periodical laws.

scholarly journals I. Note on an extension of the comparison of magnetic disturbances with magnetic effects inferred from observed terrestrial galvanic currents; and discussion of the magnetic effects inferred from galvanic currents on days of tranquil magnetism

1870 ◽  
Vol 18 (114-122) ◽  
pp. 183-185
Keyword(s):  
Magnetic Force ◽  
The Self ◽  
Instrumental Error ◽  
Magnetic Disturbance ◽  
Magnetic Effects ◽  
Royal Observatory ◽  
Moderate Disturbance ◽  
Magnetic Disturbances ◽  
Made In

The author, after referring to his paper in the Philosophical Transactions for 1868 on the comparison of Magnetic Disturbances inferred from Galvanic Currents recorded by the Self-registering Galvanometers of the Royal Observatory of Greenwich with the Magnetic Disturbances registered by the Magnetometers, on 17 days, states that he had now undertaken the examination of the whole of the Galvanic Currents recorded during the establishment of the Croydon and Dartford wires (from 1865 April 1 to 1867 October 24). The days of observation were divided into three groups,—No. I containing days of considerable magnetic disturbance, and therein including not only the 17 days above mentioned, but also 36 additional days, No. 2 containing days of moderate disturbance, of which no further use was made, and No. 3 containing the days of tranquil magnetism. The comparisons of the additional 36 disturbed days were made in the same manner as those of the preceding 17 days, and the inferences were the same. The results were shown in the same manner, by comparison of curves, which were exhibited to the Society. The points most worthy of notice are, that the general agreement of the strong irregularities, Galvanic and Magnetic, is very close, that the galvanic irregularities usually precede the magnetic, in time, and that the northerly magnetic force appears to be increased. The author remarks that no records appeared open to doubt as regards instrumental error, except those of western declination; and to remove this he had compared the Greenwich Curves with the Kew Curves, and had found them absolutely identical.

scholarly journals Vulnerability and Site Effects in Earthquake Disasters in Armenia (Colombia). II – Observed Damages and Vulnerability

2020 ◽  
Author(s):  
Francisco J. Chávez-García ◽  
Hugo Monsalve-Jaramillo ◽  
Joaquín Vila-Ortega
Keyword(s):  
Relative Frequency ◽  
Site Effects ◽  
Building Stock ◽  
Vulnerability Evaluation ◽  
Made In

Abstract. Damage in Armenia, Colombia, for the 1999 (Mw6.2) event was disproportionate. We analyse the damage report as a function of number of storeys and construction age. We recovered two vulnerability evaluations made in Armenia in 1993 and in 2004. We compare the results of the 1993 evaluation with damages observed in 1999 and show that the vulnerability evaluation made in 1993 could have predicted the relative frequency of damage observed in 1999. Our results show that vulnerability of the building stock was the major factor behind damage observed in 1999. Moreover, it showed no significant reduction between 1999 and 2004.

scholarly journals On some expressions for the radial and axial components of the magnetic force in the interior of solenoids of circular cross-section

1899 ◽  
Vol 64 (402-411) ◽  
pp. 192-202 ◽  
Keyword(s):  
Cross Section ◽  
Spherical Harmonics ◽  
Spherical Harmonic ◽  
Magnetic Force ◽  
Circular Cross Section ◽  
Total Force ◽  
Harmonic Method ◽  
Zonal Harmonics ◽  
Derivatives Of ◽  
Spherical Harmonic Method

In the present paper, certain expressions are arrived at, in terms of zonal spherical harmonics and their first derivatives, by which the values of the two components of the magnetic force may be calculated for any point in the interior of a coil, and hence the total force may be found both in magnitude and direction. The resulting series suffer from the well-known defect in the spherical harmonic method, in that they are not very rapidly converging for points near the boundary of the space for which they apply. A table of the values of the first derivatives of the first seven zonal harmonics is added.

SECULAR CHANGES OF THE MAGNETIC ELEMENTS, OTTAWA, 1500–1930

1933 ◽  
Vol 9 (1) ◽  
pp. 94-96
Author(s):  
W. H. Herbert
Keyword(s):  
Magnetic Force ◽  
Secular Changes ◽  
Terrestrial Magnetism ◽  
Permanent Change ◽  
Magnetic Elements ◽  
Made In

In this paper is presented a table of the various elements of terrestrial magnetism at Ottawa from 1500 to 1930 and explains how the values were derived from old magnetic observations made in America, and not from theory. Among other points, it shows that though the total magnetic force has been declining at Ottawa for some time, yet the total magnetic force and the magnetic elements evidently go through cycles and none have apparently suffered permanent change during the time considered.

scholarly journals XIII. Results deduced from the measures of terrestrial magnetic force in the horizontal plane, at the Royal Observatoy, Greenwich, from 1841 to 1876

1885 ◽  
Vol 176 ◽  
pp. 679-689
Keyword(s):  
Royal Society ◽  
Horizontal Plane ◽  
Magnetic Force ◽  
Proper Part ◽  
Royal Navy ◽  
Sliding Windows ◽  
Short Statement ◽  
Royal Observatory ◽  
Real Progress ◽  
Made In

In offering to the Royal Society some results deduced from the systems of magnetic observation and magnetic self-registration established several years since at the Royal Observatory, Greenwich, during a portion of the time in which I presided over that institution, I think it desirable to premise a short statement on the origin of the Magnetic Department of the Royal Observatory, and on the successive steps in its constitution. It appears to have been recognised many years ago, that magnetic determinations would form a proper part of the business of the Royal Observatory. When I commenced residence at the Royal Observatory, at the end of 1835, I found in the garden a small wooden building, evidently intended for the examination of compasses, perhaps of the size of those used in the Royal Navy. But the locality was inconvenient, and the structure was totally unfit for any delicate magnetic purpose; for instance, the balance-weights of the sliding windows were of iron. For some preliminary experiments a small observatory was borrowed from Captain Fitzroy, but no real progress was made in magnetism.

XV. On periodical laws discoverable in the mean effects of the larger magnetic disturbances.—No. III

1856 ◽  
Vol 146 ◽  
pp. 357-374 ◽  
Keyword(s):  
Royal Society ◽  
The State ◽  
Total Force ◽  
Vertical Force ◽  
Magnetic Forces ◽  
The Hours ◽  
The Mean ◽  
Magnetic Disturbances

Having at length completed the analysis of the larger disturbances of the horizontal and vertical magnetic forces at Toronto during five years of hourly observa­tion, with a view to the development of the periodical laws which regulate the occur­rence of the occasional disturbances of those elements, and of their theoretical equiva­lents, the Inclination and Total Force, I now propose to lay before the Royal Society a condensed view of the mode in which the investigation has been made, and of its results. The hourly observations of the Bifilar and Vertical Force Magnetometers during the five years terminating June 30, 1848, were received at Woolwich, from Toronto, precisely in the state in which they are printed in the second and third volumes of the 'Observations at the Toronto Observatory'; namely, the readings, uncorrected for temperature, at every hour of Göttingen time, arranged in Monthly tables, accom­panied by corresponding tables of the temperature of the magnets, shown by thermo­meters of which the balls were enclosed in the same case with the magnets, and which were read contemporaneously with the Bifilar and Vertical Force scales. The Monthly tables of the scale-readings and of the temperatures were summed before their transmission to Woolwich, both in vertical and horizontal columns, and means were taken of all the days in the month at the different hours, and of all the hours of the day on the different days, forming "hourly means” and "daily means.” In this state the observations were received at Woolwich and subsequently printed; they were, in fact, printed from the original manuscripts.

XXII. Account of some remarkable caves in the Principality of Bayreuth, and of the fossil bones found therein. Extracted from a paper sent, with specimens of the bones, as a present to the Royal Society, by his most Serene Highness the Margrave of Anspach, &c

1794 ◽  
Vol 84 ◽  
pp. 402-406
Keyword(s):  
Royal Society ◽  
Carpathian Mountains ◽  
Main Road ◽  
Fossil Bones ◽  
Different Parts ◽  
Made In

A ridge of primeval mountains runs almost through Germany, in a direction nearly from west to east; the Hartz, the mountains of Thuringia, the Fichtelberg in Franconia, are different parts of it, which in their farther extent constitute the Riesenberg, and join the Carpathian mountains; the highest parts of this ridge are granite, and are flanked by alluvial and stratified mountains, consisting chiefly of limestone, marl, and sandstone; such at least is the tract of hills in which the caves to bé spoken of are situated, and over these hills the main road leads from Bayreuth to Erlang, or Nurenberg. Half way to this town lies Streitberg, where there is a post, and but three or four English miles distant from thence are the caves mentioned, near Gailenreuth and Klausstein, two small villages, insignificant in themselves, but become famous for the discoveries made in their neighbourhood. The tract of hills is there broken off by many small and narrow vallies, confined mostly by steep and high rocks, here and there overhanging, and threatening, as it were, to fall and crush all beneath; and every where thereabouts are to be met with objects, which suggest the idea of their being evident vestiges of some general and mighty catastrophe which happened in the primeval times of the globe.

scholarly journals An experiment on electro-magnetic rotation

1876 ◽  
Vol 24 (164-170) ◽  
pp. 403-407
Keyword(s):  
Short Distance ◽  
Magnetic Force ◽  
Magnetic Polarity ◽  
The Other ◽  
Magnetic Rotation ◽  
Magnetic Pole ◽  
Left Handed ◽  
Spiral Form ◽  
Electro Magnetic ◽  
Made In

The phenomena of the rotation of movable conductors, carrying currents, about lines of magnetic force are well known. One form of experiment, commonly called the rotating spark, presents, beside the actual rotation, some peculiar features which do not appear to have been noticed in detail. The instrumental arrangements consist of a partially exhausted chamber with a platinum point for one terminal, a ring for the other, and the intervening air or other gas for the movable conductor. The chamber is made in the form of a double cylinder, so that a magnet inserted through the ring may reach nearly to the point. The discharge then passes between the point and the ring, and revolves about the magnet according to Ampere’s law. But beside the rotation, and even when, through weakening of the magnet, rotation does not actually take place, the spark, when carefully observed, is seen to assume a spiral form ; and the spiral is right-handed or left-handed according to both the direction of the current and the magnetic polarity. This effect is particularly noticeable if the magnetic pole be inserted only a short distance beyond the ring. The discharge is then seen to spread itself out sheetwise on the ring in the direction in which rotation would take place. The edge of the sheet is in the form of a helix.

Recent Work on the Phacopidae

1927 ◽  
Vol 64 (7) ◽  
pp. 308-322 ◽  
Author(s):  
F. R. Cowper Reed
Keyword(s):  
Recent Work ◽  
Present Author ◽  
New Genera ◽  
The World ◽  
Different Parts ◽  
Made In

Since the publication of the paper by the present author in 1905 on the Classification of the Phacopidae, a considerable advance has been made in our knowledge of this family as a result of further and better material being obtained, and of new discoveries in different parts of the world. Many new genera and subgenera have been instituted, and modifications or limitations of some of the old terms have been introduced by various authors. The work of Wedekind, Clarke, Rud. and E. Richter, and Kozlowski has specially dealt with questions of classification, but there is still a considerable amount of diversity in the usage and application of the generic and subgeneric names.

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