The globular cluster system of the Galaxy. II. The spatial and metallicity distributions, the second parameter phenomenon, and the formation of the cluster system.

Metal abundance measurements that were made for 84 globular clusters are used to describe the cluster system of the Galaxy. There is a metal abundance gradient between the clusters within 9 kpc of the galactic center and the clusters more distant than 9 kpc. There is a metal abundance gradient with distance from the galactic plane among the clusters within 9 kpc of the galactic center. The strength of the second parameter phenomenon varies systematically with galactocentric distance; hence regardless of whether this phenomenon is caused by age or composition variations, it is related to the large-scale evolution of the Galaxy. If age is the second parameter, then the outer halo clusters formed later over a longer period of time than the metal-poor clusters in the inner halo.