Dynamics of clusters of galaxies.

New samples of radial velocity data for three galaxy clusters are presented, and simple types of models of the X-ray emission sources of these clusters are discussed. Mean redshift and dispersion, the radial velocity as a function of distance of a galaxy from the cluster center, and velocity histograms for the clusters are shown. It is concluded that if the density distribution follows King's (1966) model, the potential of gravitational potential of a cluster can be determined from the observed velocity dispersion and galaxy counts in rings about the cluster center. The simplest models of the X-ray surface brightness can be constructed simply by considering the density and temperature distribution of gas in the potential defined by the King model.