A possible solution came in sight, when in 1889 Oliver Heaviside derived from the Maxwell's equations that the magnetic vector potential field around a moving body is altered by a factor of . Based on that result and to bring the hypothesis of an immobile ether in accordance with the Michelson–Morley experiment, George FitzGerald in 1889 (qualitatively) and independently of him Lorentz in 1892[A 2] (already quantitatively) suggested that not only the electrostatic fields, but also the molecular forces are affected in such a way that the dimension of a body in the line of motion is less by the value than the dimension perpendicularly to the line of motion. However, an observer co-moving with the earth would not notice this contraction, because all other instruments contract at the same ratio.