New variable stars in the direction of the bright cloud B in Sagittarius

621 new variable stars have been detected in a field of 5.5 degrees *5.5 degrees in the direction of the galactic centre on plates obtained with the Schmidt telescopes of the Mount Palomar Observatory (1968) and of the European Southern Observatory (1976 to 1980). The parameters alpha , delta , 1, b, R(Max), R(Min) and delta m for these variable stars have been determined from astrometric measurements at ESO-CERN and photometric measurements at CDCA. It is found from the delta m/N histogram that 379 variable stars have an amplitude of variation between 0.5 and 2.0 magnitudes. The number of variable stars is found to decrease rapidly towards large amplitudes. As a result of these observations the surface density of known variable stars in this field has increased from 2 to 21 per square degree