Title picture (at the top of every page)
The picture above (and at the top of every page) also appears on the cover (and page 248) of The Business of Transatlantic Migration.
It comes from New York Times, May 3, 1908, part 5, p. 3,
"Romance of the modern world afloat."
The illustration represents "the number of transatlantic passenger steamships of the larger types constantll afloat between the United States and European ports," taking as a rough indicator, the final week of April, 1908 when 60 passenger liners were "hurrying over the transatlantic lanes, 30 bound east and 30 steaming west."
Voyage database numbers corroborate this quantification as
an approximate early 20th century average, indicating about
28 ships traveling each way across the North Atlantic.