How the Epping Net Connects to Calais
Harold E. Nelson
14 Hill Avenue,
Newport, ME 04953
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This is from a Coast Survey Annual Report and shows how the Epping Base connects to Calais Observatory.
This type of triangulation stretched all the way to Louisiana, and as the railroads went west, so did the Coast Survey. Along the coast, there are intricately more secondary triangulation that brought the First Order backbone control to the areas to be mapped, particularly along the coast, rivers and border. Coast Survey triangulation also pushed as far north as Vanceboro as the 20th Century approached, then the International Boundary Commission built upon this network to place the boundary Range Markers along the St. Croix. Hassler's foundation of triangulation, astronomic, and baseline measures, with the superstructure that Bache placed upon it, actually knitted the United States together in one complete map....eventually (with the help of the U.S. Geological Survey).
The letters A. M. means astronomic and magnetic measurements were taken at that station. Astronomic could mean either for latitude or longitude, but stations like HUMPBACK on Lead Mountain near Beddington had observations with a Zenith Telescope for latitude, as for longitude, you would have needed a telegraph line. Cost prohibitive. Note at CHAMCOOK, only magnetic observations were taken in addition to horizontal angles.
As a side note, today, while looking at a triangulation diagram of Portland, I found a point called A W LONGFELLOW E CHIMNEY, which I have lat and long for now in my GPS, so I can look for Mr. Longfellow's house off Brighton Avenue. It will be interesting to see if it is still in the family, or if it still exists.
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