Page:Michelson1904.djvu/4

$v$ is the velocity of the earth in its orbit, $\mathrm {R}$ the radius of earth's orbit, and $\delta$ the sun's declination.

If $\mathrm {A}$=10×10 kilometres,

${\begin{alignedat}{3}v/\mathrm {V} =&\ 10^{-4},&\mathrm {R} =&\ 1.5\times 10^{11},&\lambda =&\ 5\times 10^{-7}\\\sin \phi =&\ 0.7,&\quad \cos \delta =&\ 1,&{\text{then }}\Delta =&\ 0.37\end{alignedat}}$

To obtain this displacement would require a circuit 40 kilometres in length.