scholarly journals On the diurnal variation of the magnetic declination of St. Helena

1851 ◽  
Vol 5 ◽  
pp. 664-664
Keyword(s):  
Diurnal Variation ◽  
Northern Hemisphere ◽  
Opposite Direction ◽  
Diurnal Variations ◽  
The Sun ◽  
The Earth ◽  
Magnetic Declination ◽  
St Helena ◽  
Magnetic Needle

It has long been known that the diurnal variation of the magnetic needle is in an opposite direction in the southern, to what it is in the northern hemisphere; and it was therefore proposed as a pro­blem by Arago, Humboldt and others, to determine whether there exists any intermediate line of stations on the earth where those diurnal variations disappear. The results recorded in the present paper are founded on observations made at St. Helena during the five consecutive years, from 1841 to 1845 inclusive; and also on similar observations made at Singapore, in the years 1841 and 1842; and show that at these stations, which are intermediate between the northern and southern magnetic hemispheres, the diurnal variations still take place; but those peculiar to each hemisphere prevail at opposite seasons of the year, apparently in accordance with the position of the sun with relation to the earth’s equator.

scholarly journals I. On the nature of the sun's magnetic action upon the earth

1863 ◽  
Vol 12 ◽  
pp. 567-567
Keyword(s):  
Diurnal Variation ◽  
Constant Coefficient ◽  
Direct Action ◽  
Diurnal Variations ◽  
The Sun ◽  
Normal Position ◽  
The Earth ◽  
Constant Angle ◽  
Sufficient Power ◽  
Magnetic Action

If the sun were a magnet of sufficient power to exert a sensible attraction upon a small magnet at the distance of the earth, it would have a real influence on the earth by inducing magnetism in its soft iron, and an apparent one due to the direct action of the sun upon the magnets used for measuring the earth’s variations of force. As the earth rotates upon its axis, producing a varying relation, as to position, of the place of observation with respect to the sun, a diurnal variation will thus be produced in the forces which act upon the magnetometers, which variation is shown to follow the simple law x = A sin ( h + α), x being the deviation of the magnet from its normal position, h the hour-angle of the sun (and for a single day), A a constant coefficient, and a α constant angle. A comparison of this result with the laws of the observed diurnal variations shows that direct and inducing action of the sun is not the sole cause of the variations.

XLV.—On the Diurnal Variation of the Magnetic Declination at Trevandrum, near the Magnetic Equator, and in both Hemispheres

1867 ◽  
Vol 24 (3) ◽  
pp. 669-690
Author(s):  
John Allan Broun
Keyword(s):  
Diurnal Variation ◽  
Magnetic Equator ◽  
Magnetic Declination ◽  
St Helena ◽  
Magnetic Needle ◽  
Made In

The first observations of the diurnal variation of magnetic declination, made near the equator, seem to have been those of Mr Macdonald, who observed in 1794–95 at Fort Marlborough, Sumatra, 3° 46′ S., and at St Helena. Two conclusions seem to have been deduced from these observations—1st, That near the equator the range of the diurnal variation was much smaller than in Europe; 2d, That the needle moved in opposite directions south of the equator and in Europe. This latter conclusion was made use of by M. Arago, in his report made in 1821, on the “Voyage de l'Uranie,” as the base of a hypothesis that there must be a line betwixt the two hemispheres on which the magnetic needle moves neither east nor west—that is, remains stationary. M. de Freycinet's observations showed that this line was not the terrestrial equator, and M. Arago supposed it must be the magnetic equator.

Les causes du magnétisme terrestre prouvées

1851 ◽  
Vol 5 ◽  
pp. 978-979
Keyword(s):  
Diurnal Variations ◽  
The Sun ◽  
The South ◽  
Terrestrial Magnetism ◽  
Aurora Borealis ◽  
The North ◽  
The Earth ◽  
Secular Variations ◽  
Magnetic Needle

The author considers the elements of terrestrial magnetism to be, that the force with which the magnetic needle maintains its position is not everywhere the same, and that its declination and inclination vary from one region to another. These elements, he states, undergo very different modifications, which may be reduced to the following:― 1. Variations with reference to the position of the sun to the south or to the north of the equator; 2. diurnal variations in different regions of the earth; 3. disturbances which proceed from changes of weather, and from volcanic irruptions, and those which are observed during the appearance of the aurora borealis; 4. secular variations.

I. On the lunar variations of magnetic declination at Bombay

1872 ◽  
Vol 20 (130-138) ◽  
pp. 135-136
Keyword(s):  
Diurnal Variation ◽  
Relative Position ◽  
Diurnal Variations ◽  
The Sun ◽  
The Moon ◽  
Feature Correspondence ◽  
Magnetic Declination ◽  
Variation Curve ◽  
Ordinary Character ◽  
The Mean

This paper is in continuation of that “On the Solar Variations of Magnetic Declination at Bombay,” published in the Philosophical Transactions for 1869; but the discussion is confined to the observations of the years 1861 to 1863, which alone have as yet been reduced. The point of principal interest brought out in the discussion is that whilst the mean lunar-diurnal variation is of the ordinary character, having as its principal feature a double oscillation in the lunar day, its range is very small as compared with the several ranges of the lunar-diurnal variations when the sun and moon have several specific varieties of relative position; and moreover, although in those latter variations the double oscillation is generally preserved as a main feature, correspondence of phase in the representative curves is as generally absent; and in some cases the curves are, whilst systematic, altogether different in character from the mean lunar-diurnal variation curve. The semiannual inequality in the lunar-diurnal variation, whilst it is as definitely systematic, has twice the range of the mean lunar, diurnal variation; and it is also subject to remarkable modifications which accompany changes of phase of the moon.

scholarly journals X. Note on the lunar-diurnal variation of magnetic declination

1868 ◽  
Vol 16 ◽  
pp. 59-60
Keyword(s):  
Diurnal Variation ◽  
Royal Society ◽  
Diurnal Variations ◽  
Magnetic Equator ◽  
The Other ◽  
The Sun ◽  
Magnetic Declination ◽  
Royal Society Of London

I received late last night No. 91 of the Proceedings of the Royal Society, and desire to offer the following remarks on the abstract of a paper by Mr. Neumayer which I find therein (vol. xv. p. 414). Mr. Neumayer is evidently unacquainted with the Note by me, read to the Royal Society of London in 1861 (Proc. Roy. Soc. vol. x. p. 475), in which I stated as result of the discussions of five years’ observations at Trevandrum (near the magnetic equator) that the lunar-diurnal variation of magnetic declination became inverted, like the solar-diurnal variation, when the sun passed from one hemisphere to the other, both the solar- and lunar-diurnal variations depending on the position of the sun.

3. On the Lunar Diurnal Variation of Magnetic Declination at Trevandrum, near the Magnetic Equator

1872 ◽  
Vol 7 ◽  
pp. 756-758
Author(s):  
J. A. Broun
Keyword(s):  
Diurnal Variation ◽  
Diurnal Variations ◽  
Magnetic Equator ◽  
Magnetic Declination ◽  
The Law ◽  
The Times

The author gives the results derived from different discussions of nearly eighty thousand observations, made hourly during the eleven years 1854 to 1864. They are as follows:—1. That the lunar diurnal variation consists of a double maximum and minimum in each month of the year.2. That in December and January the maxima occur near the times of the moon's upper and lower passages of the meridian; while in June and July they occur six hours later, the minima then occurring near the times of the two passages.3. The change of the law for December and January to that for June and July does not happen, as in the case of the solar diurnal variations, by leaps in the course of a month (those of March and October), but more or less gradually for the different maxima and minima.

scholarly journals Methods to Test the “Dimming Effect” Produced by a Decrease in the Number of Photons Received from Receding Light Sources

2020 ◽  
Author(s):  
Mark Zilberman
Keyword(s):  
Light Source ◽  
Opposite Direction ◽  
Ecliptic Plane ◽  
Light Sources ◽  
The Sun ◽  
Decimal Point ◽  
Relativistic Systems ◽  
The Earth ◽  
New Models ◽  
Direction Opposite

The hypothetical “Dimming Effect” describes the change of the number of photons arriving from a moving light source per unit of time. In non-relativistic systems, the “Dimming effect” may occur due to the growing distance of light sources moving away from the receiver. This means that due to the growing distance, the photons continuously require more time to reach the receiver, which reduces the number of received photons per time unit compared to the number of emitted photons. Understandably, the proposed “Dimming effect” must be tested (confirmed or rejected) through observations. a. This article provides the formula for the calculation of “Dimming effect” values using the redshift parameter Z widely used in astronomy. b. The “Dimming effect” can possibly be detected utilizing the orbital movement of the Earth around the Sun. In accordance to the “Dimming effect”, observers on Earth will view 1.0001 more photons per time unit emitted by stars located near the ecliptic plane in the direction of the Earth orbiting the Sun. And, in contrast, observers will view only 0.9999 photons per time unit emitted by stars located near the ecliptic plane in the direction opposite to the Earth orbiting the Sun. Calculating precise measurements of the same stars within a 6-month period can possibly detect this difference. These changes in brightness are not only for specific stars, as the change in brightness takes place for all stars near the ecliptic in the direction of the Earth’s orbit around the Sun and in the opposite direction. c. The “Dimming effect” can possibly be detected in a physics laboratory using a moving light source (or mirror) and photon counters located in the direction of travel and in the opposite direction. d. In theory, Dilation of time can also be used for testing the existence of the “Dimming effect.” However, in experiments on Earth this effect appears in only the 14th digit after the decimal point and testing does not appear to be feasible. e. Why is it important to test the “Dimming effect?” If confirmed, it would allow astronomers to adjust values of "Standard Candles" used in astronomy. Since “Standard Candles” are critical in various cosmological models, the “Dimming effect” can correct models and/or reveal and support new models. If it is proved that the “Dimming effect” does not exist, it will mean that the number of photons arriving per unit of time does not depend on the speed of the light source and observer, which is not so apparent.

scholarly journals On the variable intensity of ter­restrial magnetism, and the influence of the aurora borealis upon it

1837 ◽  
Vol 3 ◽  
pp. 37-38
Keyword(s):  
Magnetic Force ◽  
The Sun ◽  
South Pole ◽  
Variable Intensity ◽  
Aurora Borealis ◽  
The North ◽  
The Earth ◽  
Northern Latitudes ◽  
Snow Storms ◽  
Magnetic Needle

The author gives the results of a series of observations on the vibrations of the magnetic needle, which he undertook last summer, for the purpose of ascertaining whether the intensity of its directive force is affected by the changes in the earth’s distance from the sun, or by its declination with respect to the plane of its equator. He observed that the magnetic intensity is subject to frequent variations, which are sometimes sudden, and of short duration. These anomalies he has been unable to refer to any obvious cause, except when they were accompanied by the appearance of the aurora borealis, which evidently affected the needle on many occasions. He also thinks that the vibrations of the needle became less rapid with a moist atmosphere, and more so when it was very dry. Changes of the wind and snow storms appeared also to be attended with fluc­tuations in the intensity of the magnetism. He endeavoured to ascertain whether there existed any decided and constant difference in the directive force of each pole; conceiving that, on the hypothesis of a central magnetic force, the north pole of the magnet would, in these northern latitudes, be acted upon with much greater energy than the south pole. From his observing that the relative intensity of the two poles is not always the same, he infers the probability of the earth’s magnetism being derived from the agency of electric currents existing under its surface as well as above it, and that the rapid fluctuations in its intensity are owing to meteorological changes. The author is led to conclude that the aurora borealis is an elec­trical phenomenon, and that it usually moves during the night nearly from north to south, and in an opposite direction during the day ; that it is of the nature of positive electricity; and that its elevation above the earth is much greater than a thousand, and perhaps thou­sands of miles.

scholarly journals II. On the lunar diurnal variation of magnetic declination at the magnetic equator

1860 ◽  
Vol 10 ◽  
pp. 475-484
Keyword(s):  
Diurnal Variation ◽  
Careful Consideration ◽  
Magnetic Equator ◽  
Careful Examination ◽  
The Sun ◽  
The Moon ◽  
Magnetic Declination ◽  
The Law

This variation, first obtained by M. Kreil, next by myself, and afterwards by General Sabine, presents several anomalies which require careful consideration, and especially a careful examination of the methods employed to obtain the results. The law obtained seems to vary from place to place even in the same hemisphere and in the same latitude, and this to such an extent, that, for example, when the moon is on the inferior meridian at Toronto it produces a minimum of westerly declination; while for the moon on the inferior meridian of Prague and Makerstoun in Scotland it produces a maximum of westerly declination. No two places have as yet given exactly the same result; though the result for each place has been confirmed by the discussion of different periods. In order to obtain the lunar diurnal action, it has been usual to consider the magnetic declination at any time as depending on the sun’s and moon’s hour-angles and on irregular causes. Thus, if at conjunction, H 0 be the variation due to the sun on the meridian, and h 0 be that due to the moon on the meridian, H, the variation for the sun at 1 h , h 1 for the moon on the meridian of 1 h , and so on; it is supposed that we may represent the variations for a series of days by the following expressions, where the nearest values of h to the whole hour-angles are given:-

Diurnal Variations in Urinary Mercury Excretion

1984 ◽  
Vol 3 (6) ◽  
pp. 463-467 ◽  
Author(s):  
I.M. Calder ◽  
G.R. Kelman ◽  
H. Mason
Keyword(s):  
Diurnal Variation ◽  
Biological Monitoring ◽  
Opposite Direction ◽  
Mercury Concentration ◽  
Diurnal Variations ◽  
Creatinine Excretion ◽  
Urinary Mercury ◽  
Exposed Workers ◽  
Occupationally Exposed ◽  
Late Evening

A consistent diurnal variation of urinary mercury concentration (expressed as nmol of mercury/mmol of creatinine) has been demonstrated in 36 occupationally exposed workers, the concentration being highest in the morning and lowest in the late evening. This variation is partly intrinsic and partly an artifact because creatinine excretion also varies diurnally, but in the opposite direction. The implications of these findings in relation to the biological monitoring of mercury workers is discussed.

Sign in / Sign up

Export Citation Format

Share Document