H I Clouds with Spin Temperatures Less than 25'K. H. Physical Properties of 'two Neutral Hydrogen Clouds

Narrow-band observations of two neutral hydrogen clouds near 1=2300, b = +450 have been used to study the variation of velocity, temperature, and density in the clouds. One of the clouds has a fairly con- stant spin temperature of 24 K and is very elongated; the other has a more variable temperature with a mean value of about 17 K, and is slowly rotating. If the clouds are in pressure equilibrium with the inter- stellar medium, their masses are very low, about 0.2 M Q, and their distances are about 20 pc.