¹ Some secondary purposes will not be reviewed here because of limited space. Briefly, they are a reexamination of trade patterns (especially the notion of triangular trades) in light of total tonnage movements, the derivation of ownership proportions by route, and an analysis of comparative advantage in shipping to explain the variation in ownership by route. To do this I have relied heavily on the manuscript sources of the Public Records Office, London, especially the Colonial Naval Lists and the Customs 16/1.

² A precise measure of productivity change would require a quantitative measure of output changes per units of input. However, such an ideal measure is not possible given the available data.

³ The sources of these data are many. Though some of them are available in published form, I have relied primarily on manuscript sources available in the many historical societies, libraries, and archives on the East Coast and in England.

⁴ Average ship size, crew size, armaments, sea time, and port time have been derived from the Naval Office Lists of American and Caribbean ports. These Lists are available at the Public Records Office, London, and the University of California at Berkeley in the care of Professor Lawrence A. Harper. I have not attempted to compute changes in load-factor over time, and the analysis assumes that utilization held constant.

⁵ Philadelphia port times show that large vessels were in port more than twice as long on an average as small vessels. Port times for Philadelphia were derived from an unpublished paper entitled “The Use of a Computer in Analyzing the Colonial Trade of Philadelphia,” given by Professor William I. Davisson at the 1965 Meetings of the Western Economic Association. His data were gathered from the Pennsylvania Gazette.