Absolute Values of the Electromotive and Magnetic Forces called into play in the Propagation of Light (108) If the equation of propagation of light is F = A cos 2[pi]/[lambda] (z - Vt) The electronic force will be P = - A 2[pi]/[lambda] V sin 2[pi]/[lambda] (z - Vt) The energy per unit of volume will be p<sup>2<\sup>/8[pi][mu]V<sup>2<\sup> Where p represents the greatest value of the electromotive force Half of this consists of magnetic and half of electric energy. The energy passing through a unit of area is W = p<sup>2<\sup>/8[pi][mu]V so that P = [square root]8[pi][mu]VW where V is the velocity of light and W is the energy communicated to unit of area by the light in a second. According to Pouillets data as calculated by Prof W Thomson* the mechanical value of direct sunlight at the Earth is 83.4 foot pounds per second per square foot This give hte maximum value of P in direct sunlight at the Earths distance from the Sun P = 60.000.000 or about 600 Daniell's cells per metre. At the Suns surface the value of P would be about 13000 Daniells cells per meter At the Earth the maximum magnetic force would be .193+ At the Sun it would be 4.13 These electromotive and magnetic forces must be conceived to be reversed twice in every vibration of light, that is more than a thousand million million times in a second. * Trans Royal Society of Edinburgh 1854 (Mechanical Energies of the Solar System) + The horizontal magnetic force at Kew is about 1.76 in metrical units.
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J. C. Maxwell’s, ‘Dynamical theory of the electromagnetic field’, 1864. From The Royal Society, PT/72/7
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