U.S. Coast Survey Chart of Boston Harbor

1847-1848 chart showing the Normal Course & Velocity of the Tidal Current at Ebb in Boston Harbor and Broad Sound. Shows current directions and velocities around the local islands and points. Shows South Boston, Thompson's Island, Pettick's Island, Deer Island, Apple Island, Broad Sound and numerous other small islands and land masses.
Relief shown by hachures.
Scale of velocity in miles per hour.

IMPORTANT NOTE:

All of our United States Coast Survey (USCS), United States Coast & Geodetic Survey (USC&GS), and similar maps and charts have been professionally unfolded and flattened using humidity baths, semi-permeable membrane and drying blotter techniques. Most others you typically see on eBay have not been, and worse, are quickly and crudely unfolded for the low quality photos you see. Unfolding these maps in that way is damaging and weakens them. Please be aware.