Tvisha Faria
Auguste Arthur de la Rive, a Swiss physicist, devoted his life to the study of electro- magnetism, electrodynamics, and electricity. Son of Charles-Gaspard de la Rive, a Swiss physician, Auguste heavily researched electric gases, specific heat capacities, the Earth’s crust, magnetic fields, forces of induction and more. One of his most rewarded inventions was the process of electroplating gold substances on brass and silver for which he won 3,000 frances from the French Academy of Sciences.
Historical Contributions
De la Rive is also acclaimed for his experiments and discoveries regarding the connections between electricity and magnetism, which are explained in his texts. Most notably, his three volumes of A Treat’ise on Electricity: In Theory and Practice, which are described as “accurate and comprehensive, and is indispensable for the scientific student of electricity.” De la rive is also referenced in many scientific publications including Mémoires de la Société de Physique et D’Histoire Naturelle de Genève and Davis’s Manual of Electricity.
Of the many influential discoveries of De la Rive, one of his most notable ones involved the process of magnetization within a current and its relationship with induction, polarity, and movement. This was demonstrated through his floating compass or “helix” experiment, which evoked future studies of electromagnetism amongst scientists such as Michael Faraday.
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Floating Compass
The video below includes re-created demonstration of De la Rive’s floating compass.
The foundations of De la Rive’s floating compass date back to the findings of other scientists including Emil Lenz and Michael Faraday. Lenz’s Law and Faraday’s Law explain the dynamics of the magnetized needle floating in the water with the copper coil attached to a bar magnet. Lenz’s Law states that the direction of the current will always flow such that it is opposite of the change in magnetic flux, or the measurement of the total magnetic field passing through a given area. Similarly, Faraday’s law allows the same coordinate system to be used for both the flux and the electromotive force (EMF).
Francis Arago determined the reasoning for the movement of the floating needle in De la Rive’s floating compass. He noticed that when the horizontal needle of a compass was suspended away other objects, it settled at true north much faster than it did without any direction. Therefore, this explains why a needle floating in water would come to rest faster because fewer oscillations are necessary before coming to rest, and the water lacks surface friction to resist the needle’s movement. Additionally, in 1820, Oersted also observed the change in movement of needles as a result of current and magnetic alternations in direction.
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Primary Sources
Attached below are some references and personal publications of De la Rive’s work in primary sources.
A Treatise on Electricity in Theory and Practice by Auguste de la Rive "A convenient and elegant manner of making this kind of action manifest consists in presenting to M. G. de la Rive's floating ring, and parallel to its plane, one of the lateral faces of a magnetised bar, taking the precaution that the centre of the ring be nearer to one of the extremities than to the middle of the bar. We then see the ring slide along the face of the magnet, resting against it on its two vertical sides ; and as soon as one of them has passed the end of the bar the ring itself turns, describing an angle of 90°, and returns as before to the middle of the magnet. Thus, although in one of the vertical sides of the ring the currents are moving in a direction contrary to that which they have in the other, yet they are both attracted by points of the same face of the magnet, situated, it is true, on different sides of the pole. The effects that we have just been describing, which were discovered and described by Faraday and by G. de la Rive, at first appeared very contrary to Ampère's theory of the nature of magnets ; in fact, according to this theory, the electrical currents, the association of which forms a magnet, ought all to have had the same direction upon the same face of a magnetised bar, and, consequently, could not have exercised contrary actions, according as they were situated between the two poles, or beyond them." (239)
Michael Faraday His Life His Work by Silvanus P. Thompson "Having in 1820 a more powerful voltaic battery in operation than previously, he repeated the operation of bringing near to the compass needle the copper wire that conveyed the current; and, laying it parallel to the needle’s direction, and over or under it, found that the needle tended to turn into a direction at right79 angles to the line of the current, the sense of the deviation depending upon the direction of flow of the current, and also on the position of the wire as to whether it were above or below the needle. A current flowing from south to north over the needle caused the north-pointing end of the needle to be deflected westwards. If the wire were vertical, so that the current flowed downwards, and a compass needle was brought near the wire on the south side, therefore tending under the earth’s directive influence to point northwards toward the wire, it was observed that the effect of the current flowing in the wire was to cause the north-pointing end of the needle to turn westwards. Or, reversing the flow of current, the effect on the needle was reversed; it now tended eastwards. All these things Oersted summed up in the phrase that “the electric conflict acts in a revolving manner” around the wire."
Repeating the Electromagnetic Experiments of Michael Faraday by John Bradley "..a small voltaic combination floated by a cork, the ends of the zinc and copper slips come through the cork and are connected above by a silked wire which has been wrapped four or five times round a cylinder, and tied so as to form a close helix about one inch in diameter. When placed on conducting water it is very obedient to the magnet and serves admirably to transfer the experiments with straight wires into similar ones with helices." (285)