# Page:WhittakerSpaceTime.djvu/2

The nature of this compensatory influence was first discovered by Fitzgerald.[1] It is, that the dimensions of material bodies are slightly altered when they are in motion relative to the æther, the linear dimensions of a body in the direction of its motion being contracted in the ratio ${\displaystyle \left(1-w^{2}/c^{2}\right)^{\frac {1}{2}}}$ : 1, where w denotes the velocity of the body and c the velocity of light. For a body moving with the speed of the Earth the ratio w/c is only 1/10,000, so the contraction is only one two-hundred—millionth.