The aim of this series is to show the spatial distribution of merchant ships – or fleets – in Europe over a hundred-year period, i.e. from 1830 to 1930. Key indicators for the potential of maritime traffic are size and built of merchant ships registered in European (nation) states. Statistically, the information on the capacity of ships is given in tons – net registered tons to be precise -, and on the maps this information is depicted as bar-graph diagrams that differentiate by benchmark years (color) and capacity of ships (height). In addition, the fleets have been differentiated by the proportions of sail or steam powered ships they contain, with steam having placed on top of the bar graphs displaying a more transparent color rendition. Data for this series has been taken from B.R. Mitchell, International Historical Statistics: Europe 1750-2000. The data is rather complete; only Portugal is missing except for the last of the four maps.