Many applications of ultrasonic pulse techniques for studying the elastic behavior of rock have already been disclosed by Hughes et al (1950, 1951, 1952, 1957), Birch (1960, 1961), Simmons (1964 a, b, 1965), Christensen (1965, 1966a & b), and others. Although similar ultrasonic pulse measurement systems have been described by Tocher (1957), Fairhurst (1961), and Gregory (1967), the system described in this paper is automatic and permits continuous monitoring of elastic wave traveltime. Once set up, the system can record elastic wave traveltime at a preset rate for nearly any time period without intervention by an operator. This automated system has been used to study effects of environment on longitudinal pulse velocity in several rocks (Podnieks et al, 1968) and to make other preliminary investigations of longitudinal pulse velocity variations in rock under external influences. This report notes also several applications to problems of current interest to investigators of the elastic properties of rock.