  We describe an experiment to measure the polarization of the Cosmic Microwave
Background (CMB) with the Degree Angular Scale Interferometer (DASI), a compact
microwave interferometer optimized to detect CMB anisotropy at multipoles 140
to 900. The telescope has operated at the Amundsen-Scott South Pole research
station since 2000 January. The telescope was retrofit as a polarimeter during
the 2000--2001 austral summer, and throughout the 2001 and 2002 austral winters
has made observations of the CMB with sensitivity to all four Stokes
parameters. The telescope performance has been extensively characterized
through observations of artificial sources, the Moon, and polarized and
unpolarized Galactic sources. In 271 days of observation, DASI has differenced
the CMB fluctuations in two fields to an rms noise level of 2.8 uK.
