A convergence of opinion on the divergence of lines: Faraday and Thomson’s discussion of diamagnetism

1982 ◽  
Vol 36 (2) ◽  
pp. 243-259 ◽  
Keyword(s):  
Field Theory ◽  
Theoretical Interpretation ◽  
Normal Science ◽  
Magnetic Forces ◽  
Experimental Findings ◽  
Experimental Researches ◽  
The Relationship ◽  
Mathematical Expertise ◽  
Lines Of Force

The number of scientists actively extending the frontiers of knowledge has always been small compared to the number engaged in what Kuhn called ‘normal science’. Many of Faraday’s contemporaries shared his interest in the relationship between electric, magnetic, and other forces. A few, such as Joule and Pliicker, were quick to take up the results reported in his Experimental Researches in Electricity . When we turn to the theoretical interpretation of these results, however, the picture is different. Until 1845 Faraday was virtually alone in developing the lines of force approach for which he became famous. In 1845 he was joined by W illiam Thomson, who had learned of Faraday’s ‘conception of electric and magnetic forces acting along curved lines’ at Glasgow, four years earlier. Of their correspondence nearly three dozen letters remain from the period 1845 to 1860. One third were written between August 1845 and July 1849, the years in which Faraday’s experimental findings and Thomson’s mathematical expertise combined to produce the first rigorous field theory of magnetism.

Experimental researches in electricity. Atmospheric magnetism, continued. Twenty-seventh series

1851 ◽  
Vol 5 ◽  
pp. 1000-1001
Keyword(s):  
Electric Current ◽  
Copper Wire ◽  
Average Temperature ◽  
Magnetic Forces ◽  
The North ◽  
The Earth ◽  
Axis Parallel ◽  
The Difference ◽  
Experimental Researches ◽  
Lines Of Force

In order to obtain an experimental representative of the action of the atmosphere when heated above or cooled below the average temperature, the author employed a ring helix of covered copper wire, through which an electric current was passed. The helix was about one inch and a half in diameter, and having the well-known system of magnetic forces, was placed with its magnetic axis parallel to a free needle: when its position was such that a needle within the ring would point with the north end downward, then the effect in deflecting the surrounding lines of force of the earth was considered as like that of a relatively paramagnetic mass of air: and when its position was reversed, its action was representative of that of a heated or relatively diamagnetic mass of air. Bringing this helix into the vicinity of small magnetic needles, suspended either freely, or so as to show declination or inclination, the planes of action or indifference as regards the power of deflecting the lines of force and the needle were observed. When the needle can move only in one plane, there are four quadrants, formed (in the case of the declination needle) by the intersection of the planes of the magnetic equator and meridian. When in these planes there is no deflection at the needle, but when in the quadrants there is, and in opposite directions in the neighbouring quadrants. As the lines of force are held in and by the earth, so these experiments were repeated with a needle in near vicinity to a magnet, and the difference of effect is pointed out: then the extent to which these results are applicable to those of the earth is considered, and their utility in guiding the inquirer.

Emerson's Atom and the Matter of Suffering

2009 ◽  
Vol 64 (1) ◽  
pp. 16-47
Author(s):  
Mark Noble
Keyword(s):  
Field Theory ◽  
Natural History ◽  
Classical Field Theory ◽  
Classical Field ◽  
The Other ◽  
History Of ◽  
The One ◽  
The Individual ◽  
Solid Bodies ◽  
Lines Of Force

This essay argues that Ralph Waldo Emerson's interest in the cutting-edge science of his generation helps to shape his understanding of persons as fluid expressions of power rather than solid bodies. In his 1872 "Natural History of Intellect," Emerson correlates the constitution of the individual mind with the tenets of Michael Faraday's classical field theory. For Faraday, experimenting with electromagnetism reveals that the atom is a node or point on a network, and that all matter is really the arrangement of energetic lines of force. This atomic model offers Emerson a technology for envisioning a materialized subjectivity that both unravels personal identity and grants access to impersonal power. On the one hand, adopting Faraday's field theory resonates with many of the affirmative philosophical and ethical claims central to Emerson's early essays. On the other hand, however, distributing the properties of Faraday's atoms onto the properties of the person also entails moments in which materialized subjects encounter their own partiality, limitation, and suffering. I suggest that Emerson represents these aspects of experience in terms that are deliberately discrepant from his conception of universal power. He presumes that if every experience boils down to the same lines of force, then the particular can be trivialized with respect to the general. As a consequence, Emerson must insulate his philosophical assertions from contamination by our most poignant experiences of limitation. The essay concludes by distinguishing Emersonian "Necessity" from Friedrich Nietzsche's similar conception of amor fati, which routes the affirmation of fate directly through suffering.

scholarly journals Production of the Siderophore 2,3-Dihydroxybenzoic Acid Is Required for Wild-Type Growth of Brucella abortus in the Presence of Erythritol under Low-Iron Conditions In Vitro

2003 ◽  
Vol 71 (5) ◽  
pp. 2927-2832 ◽  
Author(s):  
Bryan H. Bellaire ◽  
Philip H. Elzer ◽  
Cynthia L. Baldwin ◽  
R. Martin Roop
Keyword(s):  
Brucella Abortus ◽  
Reproductive Tract ◽  
Iron Acquisition ◽  
Energy Sources ◽  
Growth Defect ◽  
Wild Type ◽  
Dihydroxybenzoic Acid ◽  
Experimental Findings ◽  
The Relationship

ABSTRACT Production of the siderophore 2,3-dihyroxybenzoic acid (2,3-DHBA) is required for the wild-type virulence of Brucella abortus in cattle. A possible explanation for this requirement was uncovered when it was determined that a B. abortus dhbC mutant (BHB1) defective in 2,3-DHBA production displays marked growth restriction in comparison to its parent strain, B. abortus 2308, when cultured in the presence of erythritol under low-iron conditions. This phenotype is not displayed when these strains are cultured under low-iron conditions in the presence of other readily utilizable carbon and energy sources. The addition of either exogenous 2,3-DHBA or FeCl3 relieves this growth defect, suggesting that the inability of the B. abortus dhbC mutant to display wild-type growth in the presence of erythritol under iron-limiting conditions is due to a defect in iron acquisition. Restoring 2,3-DHBA production to the B. abortus dhbC mutant by genetic complementation abolished the erythritol-specific growth defect exhibited by this strain in low-iron medium, verifying the relationship between 2,3-DHBA production and efficient growth in the presence of erythritol under low-iron conditions. The positive correlation between 2,3-DHBA production and growth in the presence of erythritol was further substantiated by the observation that the addition of erythritol to low-iron cultures of B. abortus 2308 stimulated the production of 2,3-DHBA by increasing the transcription of the dhbCEBA operon. Correspondingly, the level of exogenous iron needed to repress dhbCEBA expression in B. abortus 2308 was also greater when this strain was cultured in the presence of erythritol than that required when it was cultured in the presence of any of the other readily utilizable carbon and energy sources tested. The tissues of the bovine reproductive tract are rich in erythritol during the latter stages of pregnancy, and the ability to metabolize erythritol is thought to be important to the virulence of B. abortus in pregnant ruminants. Consequently, the experimental findings presented here offer a plausible explanation for the attenuation of the B. abortus 2,3-DHBA-deficient mutant BHB1 in pregnant ruminants.

scholarly journals Field and Circuit Models for the Wound Foil Inductor

1976 ◽  
Vol 3 (2) ◽  
pp. 97-102
Author(s):  
P. N. Murgatroyd
Keyword(s):  
Field Theory ◽  
Electromagnetic Field ◽  
Transmission Line ◽  
Field Analysis ◽  
Distributed Parameter ◽  
Two Dimensional ◽  
Lumped Model ◽  
Electromagnetic Field Theory ◽  
Lumped Equivalent Circuit ◽  
The Relationship

The Wound Foil Inductor is an important example of inductive components with appreciable internal capacitance. It is examined from three viewpoints – electromagnetic field theory, distributed-parameter (or transmission-line), and lumped equivalent circuit. The analyses are compared, particularly in terms of phase gradients within a component, and the relationship between a two-dimensional field analysis and the now established lumped model is derived.

scholarly journals Experimental researches on vegetable assimilation and respiration. XVII.—The diurnal rhythm of assimilation in leaves of cherry laurel at “limiting” concentrations of carbon dioxide

1928 ◽  
Vol 102 (720) ◽  
pp. 467-487 ◽  
Keyword(s):  
Carbon Dioxide ◽  
General Relation ◽  
Carbon Assimilation ◽  
Simple Type ◽  
Green Cell ◽  
Water Plants ◽  
Experimental Researches ◽  
The Relationship ◽  
Direct Proportionality ◽  
Cherry Laurel

The primary general relation between external supply of carbon dioxide and rate of carbon assimilation in light by the green cells of plants has been investigated by many plant physiologists, and in general, so long as the assimilation is appreciably below the maxima permitted by the light intensity employed and by the temperature of the green cell, the relationship may be held to approximate to direct proportionality between rate of assimilation and external concentration (partial pressure) of CO 2 . The case seems most clear for water plants, where a direct proportionality has been demonstrated by Blackman and Smith, 1911 (2), for Elodea. The experiments of Brown and Escombe, 1902 (4), with land leaves, at concentrations of CO 2 up to seven times that of ordinary air, point in the same direction, and although the results of later workers with land leaves (Boysen-Jensen, 1918 (3), and Lundegardh, 1921 (7) ), do not in some other respects conform to the simple type shown by the Elodea results, yet, so far as the direct proportionality between CO 2 concentration and apparent assimilation is concerned, the position is rather strengthened than otherwise.

scholarly journals Reflecting in/on field theory in practice

Tempo Social ◽  
2018 ◽  
Vol 30 (2) ◽  
pp. 195-217
Author(s):  
Michael Grenfell
Keyword(s):  
Field Theory ◽  
Pierre Bourdieu ◽  
Theory Of Practice ◽  
Social Theorist ◽  
The Social ◽  
Key Concepts ◽  
Subject And Object ◽  
The Relationship ◽  
Object Reference

The article discuses the dimension of reflexivity within the work of the social theorist Pierre Bourdieu. It alludes to the provenance of Bourdieu’s theory of practice and the epistemology, which underpins it. Language is a key element in reflexivity, the article therefore outline’s Bourdieu approach to language and the significance it holds in the development of his key concepts, as well as the relationship between subject and object. Reference is made to the works of Habermas, Heidegger, Merleau-Ponty and others to offer a ground base in just what Bourdieusian reflexivity is and how it operates in practice. Phases and stages in methodology are referred to as well as how reflexivity should operate within them. Finally, the significance of the discussion is underlined with reference to consequent outcomes.

Is a field theory of perseverative reaching compatible with a Piagetian view?

2001 ◽  
Vol 24 (1) ◽  
pp. 53-53
Author(s):  
Lorraine McCune
Keyword(s):  
Field Theory ◽  
Embodied Cognition ◽  
Mental Representation ◽  
Theoretical Position ◽  
The Relationship

This commentary is a brief reflection on the relationship between the embodied cognition analysis and a Piagetian theoretical position. In particular, the place of A-not-B in the larger Piagetian framework and the importance of the concept of mental representation, in contrast with perceptual understanding, are noted.

Modern art history as a human science in a situation of cultural turn

2019 ◽  
Vol 11 (3) ◽  
pp. 94-106
Author(s):  
Nikolai A. Khrenov
Keyword(s):  
20Th Century ◽  
Art History ◽  
Art Criticism ◽  
Normal Science ◽  
Art Theory ◽  
Linguistic Turn ◽  
Self Protection ◽  
The Relationship ◽  
Intensive Development ◽  
Cultural Turn

Intensive development of knowledge in the 20th century, including the emergence of new sciences and humanities, constantly creates a problematic situation in the sphere of art, shifting arts designation to what in the philosophy of science is known as normal science. This is associated with the idea of art as a science that has reached a stage of maturity and consistency and, therefore, complies with its norms. The concept of art as normal science is characterized by a certain degree of conservatism, as it presupposes arts self-protection against deviations from the established methodology. However, sometimes the artistic processes of modernity require different approaches. In addition, the emergence of new humanities shifts the already established methodology of art. This happened in the first decades of the 20th century, in the era of a linguistic turn in the humanities, indicating the invasion of natural sciences in the humanities; and this is happening today, at the turn of the 21st century, in a situation of a cultural turn, the emergence and intensive development of the science of culture. The current turn requires a deeper understanding of the structure and components of art history, i.e., its sub-disciplines: art history, art theory and art criticism. The essay argues that in the situation of cultural turn the theory of art can carry out functions which the other two sub-disciplines cannot. It propounds that art theory is able to make a decisive contribution to the elucidation of two problems: the relationship between art and cultural studies and the problem of historical time, which is important both for contemporary art and for art history.

Modern art history as a human science in a situation of cultural turn

2019 ◽  
Vol 11 (1) ◽  
pp. 82-98
Author(s):  
Nicolai A. Khrenov
Keyword(s):  
20Th Century ◽  
Art History ◽  
Art Criticism ◽  
Normal Science ◽  
Art Theory ◽  
Linguistic Turn ◽  
Self Protection ◽  
The Relationship ◽  
Intensive Development ◽  
Cultural Turn

Intensive development of knowledge in the 20th century, including the emergence of new sciences and humanities, constantly creates a problematic situation in the sphere of art, shifting arts designation to what in the philosophy of science is known as normal science. This is associated with the idea of art as a science that has reached a stage of maturity and consistency and, therefore, complies with its norms. The concept of art as normal science is characterized by a certain degree of conservatism, as it presupposes arts self-protection against deviations from the established methodology. However, sometimes the artistic processes of modernity require different approaches. In addition, the emergence of new humanities shifts the already established methodology of art. This happened in the first decades of the 20th century, in the era of a linguistic turn in the humanities, indicating the invasion of natural sciences in the humanities; and this is happening today, at the turn of the 21st century, in a situation of a cultural turn, the emergence and intensive development of the science of culture. The current turn requires a deeper understanding of the structure and components of art history, i.e., its sub-disciplines: art history, art theory and art criticism. The essay argues that in the situation of cultural turn the theory of art can carry out functions which the other two sub-disciplines cannot. It propounds that art theory is able to make a decisive contribution to the elucidation of two problems: the relationship between art and cultural studies and the problem of historical time, which is important both for contemporary art and for art history.

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