The electromotive intensity, the components of which are defined by equations (B) [in cartesian coordinates], depends on three circumstances. The first of these is the motion of the particle through the magnetic field. ... It depends on the velocity of the particle transverse to the lines of magnetic induction. ... [It is] the vector part of the product of the magnetic induction multiplied by the velocity ... The third term in each of the equations (B) depends on the time-variation of the magnetic field. ... The last term of each equation (B) is due to the variation of the [electric potential] in different parts of the field. ... The electromotive intensity, as defined by equations (B), may therefore be written in the quaternion form, [vector equation for (B)].
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Published before 1923