Experiments on the influence of the aurora borealis on the magnetic needle. By the Rev. James Farquharson, F. R. S. Minister of Al­ford, Aberdeenshire. In letters addressed to Captain Edward Sa­bine, Sec. R. S

1833 ◽  
Vol 2 ◽  
pp. 391-392
Keyword(s):  
Royal Society ◽  
Magnetic Intensity ◽  
Aurora Borealis ◽  
Magnetic Declination ◽  
Stop Watch ◽  
The Mind ◽  
Magnetic Needle

In the first letter, dated from Alford, Dec. 15, 1829, the author gives a description of the instrument which was furnished to him by the Royal Society for measuring the variation of the magnetic needle, and also the magnetic intensity; and of his mode of using it. The needle was so delicately suspended as to render changes in the declination as small as 10'´ very sensible. In his experiments on the magnetic intensity, the intervals of time occupied in the needle’s performing 50 oscillations, commencing with an arc of 12°, were noted by a stop-watch, in which the stop, being applied on the ba­lance, is instantaneous in its operation. The watch is again released from the stop at the commencement of a new observation; thus com­pensating, on the principle of the repeating circle, for any inaccuracy in the reading off, or any inequality in the divisions of the dialplate. The observations made on an Aurora borealis which appeared on the night of the 14th of December, are particularly detailed. On that occasion, the disturbance of the magnetic declination was so great, and so frequently changing from east to west, and the reverse, as to leave no doubt in the mind of the author of the reality of this influence. The needle, however, was affected at those times only when the fringes of the aurora were in such a position as to include the needle in their planes. It appeared to him, also, that the side towards which the needle declined, was the quarter where the aurora gave out the most vivid light.

scholarly journals I.—Account of some Experiments made in Different Parts of Europe, on Terrestrial Magnetic Intensity, particularly with reference to the Effect of Height

1839 ◽  
Vol 14 (1) ◽  
pp. 1-29 ◽  
Author(s):  
James D. Forbes
Keyword(s):  
Royal Society ◽  
Horizontal Plane ◽  
Magnetic Intensity ◽  
Magnetic Needle ◽  
Different Parts ◽  
Made In

1. The Council of the Royal Society of Edinburgh having, on my application in 1832, entrusted me with Hansteen's Magnetic Intensity Apparatus, in their possession, I feel it to be my duty to communicate to the Society the results then and subsequently obtained with it.2. The instrument consists of a mahogany box 5 inches long, 4 broad, and 2 deep, with sides and top of glass, having also a wooden tube, screwing into the top, for containing a silk-worm's fibre about 5 inches long, by which the magnetic needle is suspended so as to place itself horizontally, and after being caused to deviate from its point of rest, the time of any given number of oscillations in a horizontal plane is measured,—whilst a graduated circle in the bottom of the box indicates its arc of vibration.

scholarly journals XXVI.—On the Decennial Period in the Range and Disturbance of the Diurnal Oscillations of the Magnetic Needle, and in the Sun-spot Area

1876 ◽  
Vol 27 (4) ◽  
pp. 563-594 ◽  
Author(s):  
J. A. Broun
Keyword(s):  
Royal Society ◽  
The Sun ◽  
Spot Area ◽  
Magnetic Declination ◽  
Scientific Reputation ◽  
The Mean ◽  
Magnetic Needle

The presentation to the Royal Society of Edinburgh of results relating to the decennial period, derived from observations of magnetic declination made during nearly a quarter of a century at Trevandrum, has seemed to me a favourable occasion for a determination of the mean duration of this period. Upon the explanation of the decennial variations depends the solution of several important problems in solar and terrestrial physics, and the first step towards this result is to ascertain the true mean duration of the period. Two markedly different results have been obtained, each of which has been accepted by men of the highest scientific reputation.

scholarly journals VI. Experiments on the influence of the aurora borealis on the magnetic needle

1830 ◽  
Vol 120 ◽  
pp. 97-115
Keyword(s):  
Rectangular Plate ◽  
Circular Plate ◽  
Royal Society ◽  
Steel Wire ◽  
Vertical Tube ◽  
Brass Tube ◽  
Aurora Borealis ◽  
Brass Plate ◽  
Flat Side ◽  
Magnetic Needle

Alford , December 15 th , 1829.—The apparatus, belonging to the Royal Society, with which these experiments were made, consists of a horizontal brass circle, about one foot in diameter, graduated to divisions of 10 minutes, and capable of adjustment to a perfect level by means of spirit levels and screwed feet. Concentrically within this divided circle moves a circular horizontal brass plate, its edge touching the divisions, and having at opposite points two verniers, which, by means of attached microscopes, indicate the movements which it makes to 60th parts of 10 minutes, or 10". The movement of the plate within the circle is effected by means of a screw. A circular brass needle-box is attached to the surface of the inner plate, and a vertical pointed steel wire for supporting the needle forms the centre. At opposite points in the needle-box are fixed two micrometers with cross wires in the foci, for adjusting the needle to a level, and observing any change in its direction. The top of the needle-box is a circular plate of ground glass in a brass ring, made to slip easily off and on, and having screwed into its centre a vertical brass tube about 8 inches long, for the purpose of suspending the needle with fibres of silk, for measuring the time of its oscillations. A horizontal brass pin, with a minute perforation for the silk near its middle, passes through the vertical tube near its top, and being contrived with several motions, serves to adjust the suspended needle, and bring it correctly over the steel point, where its levelling can be completely ascertained. The magnetic needlec itself is a rectangular plate about 5 inches long, half an inch broad, and 1/10th of an inch thick. An agate cup set in brass admits of being screwed in either at the narrow or flat side of the needle; and a little fixt ring of brass, with a minute perforation in its top, rising over the cup, admits of the ready attachment of the silk; so that the needle can be placed on the steel point or suspended with the silk, with its flat face either vertical or horizontal.

Francis Bacon and the Origins of Christian Virtuosity

2017 ◽  
Author(s):  
Victor Nuovo
Keyword(s):  
Empirical Study ◽  
Royal Society ◽  
Natural Philosophy ◽  
Francis Bacon ◽  
Human Society ◽  
Divine Revelation ◽  
Intellectual Life ◽  
Natural Philosopher ◽  
Robert Boyle ◽  
The Mind

Although the vocation of Christian virtuoso was invented and named by Robert Boyle, Francis Bacon provided the archtype. A Christian virtuoso is an experimental natural philosopher who professes Christianity, who endeavors to unite empiricism and supernatural belief in an intellectual life. In his program for the renewal of the learning Bacon prescribed that the empirical study of nature be the basis of all the sciences, including not only the study of physical things, but of human society, and literature. He insisted that natural causes only be used to explain natural events and proposed not to mix theology with natural philosophy. This became a rule of the Royal Society of London, of which Boyle was a principal founder. Bacon’s rule also had a theological use, to preserve the purity and the divine authority of revelation. In the mind of the Christian virtuoso, nature and divine revelation were separate but complementary sources of truth.

scholarly journals XXV. A letter from Mr. William Mountayne, F. R. S. to the Right Honourable James Earl of Morton, President of the Royal Society, containing some observations on the variation of the magnetic needle, made on board the Montagu Man of War, in the years 1760, 1761, and 1762, by Mr. David Ross, Surgeon

1766 ◽  
Vol 56 ◽  
pp. 216-223 ◽  
Keyword(s):  
Atlantic Ocean ◽  
Royal Society ◽  
The Earth ◽  
The Right ◽  
Magnetic Needle

My Lord, The following tables I have compared with the variation chart, published in the year 1756, and so find that they agree pretty well in general, making allowance for the time elapsed: it is true, that, in some few places in the Atlantic Ocean, they differ; yet this may probably arise, as is often the case, from an error in the Montagu's supposed longitude, where such observations were made. But the greatest difference (a greater than should arise, I think, according to common course) appears upon the coast of Portugal, Cape Saint Vincent, and about Gibraltar, near and within sight of land, where the observations are ascertained to the spot. Hence, if mine observed about the year 1756, and those of Mr. Ross's, were both near the truth, at the respective times when they were taken, I know not how to account for this considerable encrease, unless those late extraordinary convulsions, in the bowels of the earth, upon those several coasts, may be found, by further experiments, to have there influenced the directions of the magnetic needle.

scholarly journals III. Magnetical experiments and observations

1787 ◽  
Vol 77 ◽  
pp. 6-25
Keyword(s):  
Royal Society ◽  
Magnetic Needle

The Bakerian Lecture, which last year I had the honour to deliver to the Royal Society, contained the account of some magnetical experiments, particularly concerning the magnetism of brass, from which it appeared, that most brass becomes magnetic, so far as to attract the magnetic needle, by being hammered, and loses its magnetism by annealing or softening in the fire; but that there is some brass, which possesses no magnetism naturally, not acquires any by hammering.

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

1831 ◽  
Vol 121 ◽  
pp. 199-207
Keyword(s):  
The Sun ◽  
Variable Intensity ◽  
Terrestrial Magnetism ◽  
Aurora Borealis ◽  
Magnetic Attraction ◽  
Variable Force ◽  
Abstract Principle ◽  
Planetary Orbits ◽  
Magnetic Needle

In the annexed Table are given the results of a series of observations on the vibrations of the magnetic needle, which I undertook last summer, for the purpose of ascertaining whether its intensity is or is not affected by the changes in the earth’s distance from the sun, or by its declination with respect to the plane of his equator; for, if we refer the nodes of the planetary orbits to this plane, there appears to be so considerable a degree of coincidence in most of them, as would seem to imply the existence of a more definite law than we are ac­customed to attach to the abstract principle of gravitation. I am not at present prepared to say much respecting this part of my investigation; but I have obtained results, which appear to be interesting, relative to the variable force of the magnetic attraction, and the action of the aurora borealis on the direction and intensity of the needle.

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 ‘Vividness’ in english natural history and anatomy, 1650–1700

2012 ◽  
Vol 66 (4) ◽  
pp. 341-356 ◽  
Author(s):  
Alexander Wragge-Morley
Keyword(s):  
Seventeenth Century ◽  
Natural History ◽  
Royal Society ◽  
Medical Discourse ◽  
Rhetorical Strategies ◽  
Rhetorical Device ◽  
John Ray ◽  
The Mind ◽  
It Knowledge ◽  
The Brain

This article concerns the use of rhetorical strategies in the natural historical and anatomical works of the seventeenth-century Royal Society. Choosing representative works, it argues that naturalists such as Nehemiah Grew, John Ray and the neuroanatomist Thomas Willis used the rhetorical device known as ‘comparison’ to make their descriptions of natural things vivid. By turning to contemporary works of neurology such as Willis's Cerebri Anatome and contemporary rhetorical works inspired by other such descriptions of the brain and nerves, it is argued that the effects of these strategies were taken to be wide-ranging. Contemporaries understood the effects of rhetoric in terms inflected by anatomical and medical discourse—the brain was physically altered by powerful sense impressions such as those of rhetoric. I suggest that the rhetoric of natural history could have been understood in the same way and that natural history and anatomy might therefore have been understood to cultivate the mind, improving its capacity for moral judgements as well as giving it knowledge of nature.

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