  The shadowing of high-energy cosmic rays by the Moon has been observed with a
significance of 9.4 standard deviations with the L3+C muon spectrometer at
CERN. A significant effect of the Earth magnetic field is observed. Since no
event deficit on the east side of the Moon has been observed, an upper limit at
90% confidence level on the antiproton to proton ratio of 0.11 is obtained for
primary energies around 1 TeV.
