This report describes the development of a portable low-speed heat- pulse anemometer for underground mine airflow measurements. Part i describes the development of the instrument. Various physical and electrical parameters such as wire diameter, spacing of the probe wires, operating temperature of the pulsed wire, signal processing and system control, ambient thermal properties, and flow alignment were varied in a successful effort to find a method of operating a heat-pulse anemometer over the range of air velocities from 24 to 390 ft/min. Part II describes the implementation of these findings in a personal, self-contained microprocessor-based instrument measuring 6 by 7 by 2 1/2 in, with a sectioned 2-ft wand. Mechanical, aerodynamic, and electronic design details are given, and the software is documented.