Social network, an interesting theoretical cconcept, has suffered through difficulties in developing from it any operational devices suitable for use in ordinary social survey research. Here, one such device is presented, and its utility is examined in the contrasting urban contexts of Hull and Los Angeles. Existing theories about the correlates of network density are partially confirmed and partially contradicted by the findings. In particular there is an attempt to reevaluate the part played by kinship in the social networks of modern urban society.