OH observations of sixteen interstellar dust clouds

Observations in the 1665 and 1667-MHz lines of OH of 16 interstellar dust clouds of varying densities yielded OH emission from seven of the clouds. In one cloud, the 1667-MHz line is enhanced relative to the 1665-MHz line; in another, the OH optical depth is very large or the 1665-MHz line is enhanced. The observations show that the clouds have velocities in the range - 3.5 to + 9.4 km/sec, velocity widths in the range 0.7-2.2 km/sec, and column densities ranging from 9 X X 1015 molecules per cm2.