  The DIRC (Detection of Internally Reflected Cerenkov light) is a new type of
ring imaging Cerenkov detector, which detects images from Cerenkov light
produced in precisely machined quartz bars. The Cerenkov images are transported
along several meters of bar to the edge of the detector where they are
proximity focussed unto an array of conventional photomultiplier tubes. Results
from a prototype device comprising a 2 x 4 x 240 cm**3 quartz bar read by an
array of 480 PMT's are presented. Sample images, which are the first observed
in this type of detector, are shown. Measurements of the light yield
(approximately 20 photoelectrons per image) and the angular resolution are in
good agreement with Monte Carlo predictions.
