scholarly journals The Bakerian Lecture. On the best kind of steel and form for a compass needle

1833 ◽  
Vol 2 ◽  
pp. 141-142
Keyword(s):  
Magnetic Force ◽  
Magnetic Pole ◽  
North West ◽  
The Subject

On the return of the first expedition from the discovery of a North-west Passage, the compasses were reported to have become nearly useless, from the diminution of the directive force consequent upon the near approach to the magnetic pole. The azimuth compasses on that occasion being of the author’s invention, he was anxious that the second expedition should be furnished with instruments combining the utmost power and sensibility; and was consequently led to the researches, the mode of conducting which, with their results, form the subject of this lecture. In respect to the best material for the construction of compass needles, Captain Kater found that clock springs made of sheer steel were capable of receiving the greatest magnetic force, and that in forming the needle it should be exposed as little as possible to heat, by which its capability of receiving magnetism is diminished.

X. The Bakerian Lecture. On the best kind of steel and form for a compass needle

1821 ◽  
Vol 111 ◽  
pp. 104-129 ◽  
Keyword(s):  
Royal Society ◽  
Magnetic Pole ◽  
Practical Utility ◽  
North West ◽  
The Subject

On the return of the first expedition which sailed for the discovery of a north-west passage, it appeared that from the near approach to the magnetic pole, and the consequent di­-minution of the directive force, the compasses on board had become nearly useless. Some of the azimuth compasses employed on that occasion were of my own invention; I was therefore anxious that the next expedition, which was about to sail under the command of Lieutenant Parry, and which has happily returned with so much honour to those engaged in it, should be furnished with instruments of this description, com­bining as much power and sensibility as possible. It was with this intention alone that I commenced the ex­periments which form the subject of the present paper; but which I should not have deemed sufficiently important to be made public, had I not lately, on resuming the enquiry, been led to some results which appeared of sufficient interest, as well as practical utility, to induce me to lay them before the Royal Society.

III. Experimental researches in electricity. ─Twenty-fifth series

1851 ◽  
Vol 141 ◽  
pp. 29-84 ◽  
Keyword(s):  
Magnetic Force ◽  
Central Line ◽  
General View ◽  
Axial Line ◽  
Electric Induction ◽  
Other Substances ◽  
Iron Nickel ◽  
The Subject ◽  
Experimental Researches ◽  
As If

2797. The remarkable results given in a former series of these researches (2757. &c.) respecting the powerful tendency of certain gaseous substances to proceed either to or from the central line of magnetic force, according to their relation to other substances present at the same time, and yet the absence of all condensation or expansion of these bodies (2756.) which might be supposed to be consequent on such an amount of attractive or repulsive force as would be thought needful to produce this tendency and determination to particular places, have, upon consideration, led me to the idea, that if bodies possess different degrees of conducting power for magnetism, that difference may account for all the phenomena; and, further, that if such an idea be considered, it may assist in developing the nature of magnetic force. I shall therefore venture to think and speak freely on this matter for a while, for the purpose of drawing others into a consideration of the subject; though I run the risk, in doing so, of falling into error through imperfect experiments and reasoning. As yet, however, I only state the case hypothetically, and use the phrase conducting power as a general expression of the capability which bodies may possess of affecting the transmission of magnetic force; implying nothing as to how the process of conduction is carried on. Thus limited in sense, the phrase may be very useful, enabling us to take, for a time, a connected, consistent and general view of a large class of phenomena; may serve as a standard of meaning amongst them, and yet need not necessarily involve any error, inasmuch as whatever may be the principles and condition of conduction, the phenomena dependent on it must consist among themselves. 2798. If a medium having a certain conducting power occupy the magnetic field, and then a portion of another medium or substance be placed in the field having a greater conducting power, the latter will tend to draw up towards the place of greatest force, displacing the former. Such at least is the case with bodies that are freely magnetic, as iron, nickel, cobalt and their combinations (2357. 2363. 2367. &c.), and such a result is in analogy with the phenomena produced by electric induction. If a portion of still higher conducting power be brought into play, it will approach the axial line and displace that which had just gone there; so that a body having a certain amount of conducting power, will appear as if attracted in a medium of weaker power, and as if repelled in a medium of stronger power by this differential kind of action (2367. 2414.).

Virgil's Location of Corythus

1976 ◽  
Vol 26 (2) ◽  
pp. 293-295
Author(s):  
E. L. Harrison
Keyword(s):  
Recent Article ◽  
Careful Examination ◽  
North West ◽  
The North ◽  
The Subject

In a recent article JRS (1973), 68 f. Nicholas Horsfall sought to demonstrate that Corythus, which Virgil makes the original home of Dardanus (Aen. iii, 167 f.), should be identified with Tarquinii, some 50 miles north-west of Rome, on the coast of Etruria, rather than with Cortona, roughly twice as far away, to the north, and inland. In doing so he expressed surprise that the Virgilian evidence should have been completely ignored by previous writers on the subject (p. 68): and, using the Aeneid as the main source on which his own argument was based, he supported his conclusion with a careful examination of several other aspects of the problem.

scholarly journals I. On magneto-electric induction in liquids and gases.—Part I. production of induced currents in electrolytes

1878 ◽  
Vol 26 (179-184) ◽  
pp. 40-43
Keyword(s):  
Sulphuric Acid ◽  
Magnetic Force ◽  
Primary Circuit ◽  
Rubber Tube ◽  
Secondary Circuit ◽  
Negative Results ◽  
Electric Induction ◽  
The Subject ◽  
Induced Currents ◽  
Solid Conductors

This paper contains an account of an experimental inquiry into the production of induced currents in liquids by magneto-electric induction. Faraday examined one such case of induction, in which a conducting liquid was used as a secondary circuit. He coiled round the armature of an electromagnet an india-rubber tube filled with dilute sulphuric acid, and found, on making and breaking the primary circuit, the induced currents generated in it, as in the case of metallic conductors; but he could not obtain any effect when brine, sulphuric acid, or other solutions were rotated in basins over a magnet, or enclosed in tubes and passed between the poles. He failed also to detect any magneto-electric current in water flowing across the earth’s lines of magnetic force (viz. in the river Thames). Since the reason for these negative results is not at once obvious, it seemed desirable to repeat and extend them to other cases, so that, if possible, the analogy of electrolytic with solid conductors might, in respect to magneto-electric induction, be completed. In addition, the subject involves the interesting question of the magneto-electric phenomena accompanying the flow of ocean-currents and other large masses of water.

scholarly journals I. On the determination of Verdet’s constant in absolute units

1877 ◽  
Vol 167 ◽  
pp. 1-34 ◽  
Keyword(s):  
Magnetic Force ◽  
Polarized Light ◽  
The Subject

In the year 1845 Faraday discovered that if plane polarized light passes through certain media, and these media be acted on by a sufficiently powerful magnetic force, the plane of polarization is rotated. About the year 1853 M. Verdet commenced a long and exhaustive examination of the subject, and his first result was published in Ann. de Chimie et de Phys. 3 sér. tom. xli.

The verb in northern Najdi Arabic

1979 ◽  
Vol 42 (3) ◽  
pp. 467-499 ◽  
Author(s):  
Peter F. Abboud
Keyword(s):  
Saudi Arabia ◽  
North West ◽  
The North ◽  
Phonological Features ◽  
Najdi Arabic ◽  
The Subject ◽  
Object Pronouns

The dialects spoken in the Najd of Saudi Arabia have striking features which not only are unknown or unreported in other dialects but also retain some characteristics of the 'Arabiyya and of ancient dialects of the peninsula reported by the Arab grammarians. On both these counts, they are of paramount importance for synchronic, comparative and historical dialectology. Yet little is known of them and published materials remain scanty. It is the purpose of this article to describe in some detail the morphology of the verb, i.e., the stem, the subject markers and the object pronouns, and in the process, present phonological features and processes, in a dialect spoken in the North of the Najd, specifically that of Hāyil. This is an important town on the edge of the Jabal Shammar mountains just south of the Nafud, and some 350 miles to the north-west of Riyādh. Although the dialect manifests features which are typically Najdi, in the sense that investigation shows them to exist in other dialects of the Najd, it also possesses peculiarities all its own.

On Heptaphyllum, a New Genus of Carboniferous Coral

1924 ◽  
Vol 61 (9) ◽  
pp. 416-423 ◽  
Author(s):  
Arthur E. Clark
Keyword(s):  
New Genus ◽  
Growth Stages ◽  
Lower Carboniferous ◽  
North West ◽  
The North ◽  
Rugose Corals ◽  
The Subject ◽  
The Way ◽  
West Of Ireland

A few years ago Mr. Carruthers described an aberrant coral, Cryptophyllum hibernicum, from the Lower Carboniferous of Bundoran, Donegal. Cryptophyllum occurred in the Lower Calp shales, which are considered to be about at the horizon of Vaughan's C2 to S1 beds. Another aberrant genus, Heptaphyllum, also from the north-west of Ireland—Lower Carboniferous shales, Sligo—forms the subject of this paper. Cryptophyllum is remarkable, first for the manner in which the earlier major septa appear—irregularly, and nearly simultaneously, instead of regularly, and in consecutive pairs, as is typical for Rugose Corals; and also in the development of only five septa instead of the normal six in the earliest growth stages. Heptaphyllum, as its name implies, develops seven septa in the young corallum. It resembles Cryptophyllum in having an early aseptate corallum, and in the way in which the earlier septa appear.

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.

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