The rate of oxidation of unithiol (sodium dimercaptopropansulfonate) by nit
rite ion was determined in the course of the annual experiment at the Antar
ctic station Mirny in 1996-1997. The rhythmic fluctuations in the oxidation
rate were found. It is shown that these fluctuations correlate with change
s in the velocity of the Earth's forward-rotational movement by the action
of the Sun and Moon.