Friars Head signal as seen from Mt.Carmel.

Loaf Hill signal as seen from Bald Hill.

Finished view from Mt.Carmel looking to North East No.1

Finished view from Staten Island fire signal towards Manhattan.

Finished view from Staten Island fire signal towards Manhattan. View emphasizing Manhattan.

Finished easterly view from Stony Hill

Finished view from Yard Station. Graphic includes triangulation diagram extending from Mt.Holly to Mt. Hope.

Panoramic view showing Mt.Hope and Grand View from Station Montrose.

View of Diamond Hill by Ferdinand Gerdes.

View looking north from Fort Hale

Rough sketch of Newton Signal showing lines of sight to observed triangulation stations.

Title page to computations of triangles observed by Ferdinand Hassler around New York City in 1817.

Rough sketch showing the general appearance of the 30-inch theodolite when mounted.

Main triangles of the Survey of the Coast of the United States showing method of computing using logarithms.

Computation of triangles working outward from Fire Island baseline showing method of computing using logarithms.

Field observations of angles showing different plate settings of theodolite.

Computation book page showing method of determining final value of observed angle.

Computations showing method of determining links of sides of triangles by using logarithms.

Topographic shoreline manuscript showing section of Hudson River including Washington Irving's home below Tarrytown. Sheet produced by Hugo L. Dickins, registry No.T-132.

Topographic shoreline manuscript showing section of Hudson River in the vicinity of today's Tappan Zee Bridge. Sheet produced by Hugo L. Dickins, registry No.T-132.

Topographic sheet from Fort Lee to Boompers Hook by Thornton A. Jenkins, USN. Registry No. T-96

Topographic sheet between Patchogue and Smith Point, Long Island, by Charles Renard. Title block of Registry No. T-2.

Topographic sheet between Patchogue and Smith Point, Long Island, by Charles Renard. Registry No. T-2.

Western portion of Hydrographic Sheet No. H-44. This was actually the first hydrographic survey sheet completed by the U.S. Coast Survey. Surveyed by Lieutenant Thomas R. Gedney, USN.

Center portion of Hydrographic Sheet No. H-44. This was actually the first hydrographic survey sheet completed by the U.S. Coast Survey. Surveyed by Lieutenant Thomas R. Gedney, USN.

Blowup of title block of Hydrographic Sheet No. H-44 showing South Coast of Long Island, Great South Bay, 1:10,000, 1834, Lt. T. R. Gedney, USN.

Section of Hydrographic Sheet No. H-44. This was actually the first hydrographic survey sheet completed by the U.S. Coast Survey. Surveyed by hydrographic survey sheet completed by the U.S. Coast Survey. Surveyed by

Title block of Chart of Sandy Hook Bar, sounded by Lieutenant T. R. Gedney. This survey discovered Gedney's Channel into New York Harbor helping insure its place as the great mercantile capital of the United States.

Tide diagram of Chart of Sandy Hook Bar, sounded by Lieutenant T. R. Gedney. This is one of the earliest tide records of the Coast Survey. Meteorological information was also included showing an awareness of the effect of winds on tidal levels.

Blowup of tide diagram of Chart of Sandy Hook Bar by Lieutenant T.R. Gedney. Tide scale for September 1835 with meteorological and astronomical information included.

Portion of Chart of Sandy Hook Bar showing New York Bay to west of Sandy Hook.

Portion of Chart of Sandy Hook Bar showing bottom configuration between Sandy Hook and Long Island.

Portion of Chart of Sandy Hook Bar showing bottom configuration between Sandy Hook and Long Island.

SW sheet of six-sheet chart of New York Bay and Harbor. Title sheet. This chart was the culmination of Ferdinand Hassler's superintendence. Unfortunately it was published posthumously. It established the style for Coast Survey and Coast and Geodetic Survey charts for at least the next 50 years.

Title block of Sheet No. 1 which includes sailing directions, tidal information, light characteristics, and establishment of New York City Hall as Zero Longitude for this chart. Two remarkable views of Sandy Hook Light are also included.

Telescopic view of Sandy Hook Light S.W. on edge of ship channel as seen in 1839. Note glass panes.

SE sheet of six sheets of New York Bay and Harbor. This sheet shows approaches to New York Harbor from the south. It also includes an innovative tidal current chart from observations made by Lt. Comd. Charles H. Davis in 1844. Note also bottom characteristics and offshore depths coupled with incredible topographic detail on Sandy Hook.

Section of SE sheet of six sheets of New York Bay and Harbor showing False Hook Channel, the primary means of approaching New York Harbor prior to the Coast Survey work of 1835.

Note on SE sheet of six sheets of New York Bay and Harbor designating that longitudes on the chart are referred to the Meridian of New York City Hall.

Section of SE sheet of six sheets of New York Bay and Harbor showing current table and scales of both statute miles and a scale of yards. The bottom-most scale divides minutes of longitude into ten-second intervals. Although the minutes of latitude are also divided into ten second divisions, there is no scale for nautical miles perhaps reflecting Hassler's Swiss terrestrial roots.

Sheet No. 3, the west center sheet of six of New York Bay and Harbor including Staten Island, the Narrows (Verrazano Narrows today), and the western part of channels leading over Sandy Hook Bar.

Blowup of area in vicinity of channels over Sandy Hook Bar showing selected soundings, various banks and bars, white and black buoys, directions of currents , stippling for sand and mud, and bottom characteristics.

Sheet No. 4, the east center sheet of six of New York Bay and Harbor including Gedney's Channel, the newly discovered channel into New York Harbor, Coney Island, and Rockaway Beach.

Sheet No. 4, blowup of Gedney's Channel area and other channels.

Sheet No. 5, the NW sheet of six sheets of New York Bay and Harbor. This sheet includes the Hudson River north of The Narrows, lower Manhattan, Jersey City, Governors Island, Ellis Island, and Bedloe's Island.

Sheet no. 6, the NE sheet of six sheets of New York Bay and Harbor. This sheet includes eastern Manhattan, the East River, Brooklyn, Jamaica Bay, and western Long Island. The topographic detail on this sheet is amazing.

The Harbor of Annapolis. This chart may be the first one produced solely from work accomplished under the Superintendence of Alexander Dallas Bache. It includes a view of the Annapolis Capitol Building from the water.

Four views from the chart "The Harbor of Annapolis." Two of these views show the State House as seen from the water to good advantage.

Copy of sketch map by Captain J. L. Folsom of the U.S. Topographical Engineers of the vicinity of the Golden Gate and present day San Francisco. John Ross Key, a nephew of Francis Scott Key and a draftsman in the Coast Survey, copied the map for the archives of the Coast Survey.

Field map of line of soundings offshore from Cape Henlopen, Delaware Bay. In the far SE corner, the break in soundings from 85 fathoms to 145 fathoms is one of the earliest indications of the continental shelf break.