Jim Nadeau, a volunteer docent at the Portland Observatory, gave a presentation at the New Gloucester Meetinghouse on Saturday, April 18, on the history and purpose of the last remaining maritime signal tower in the United States.

Nadeau, who works as a land surveyor in Portland, regularly leads tours of the observatory during the summer. Nadeau said he was invited by his longtime friend and former employee, New Gloucester Historical Society Curator Tom Blake, to give the presentation to roughly two dozen residents of New Gloucester.

One of the attendees was Alessa Wylie, the former education coordinator for Greater Portland Landmarks, who Nadeau shouted out at the beginning of the presentation.

Nadeau began the presentation by stressing the difference between a maritime signal tower and a lighthouse. Signal towers communicated with ships via signal flags using the semaphore system, which, in the early 19th century, could send a message 125 miles in just one hour.

It is a common misconception that the observatory was a lighthouse, even being featured in a video compilation at the Maine Lighthouse Museum in Rockland.

The history of the observatory dates back to 1807, when the land it is located on was purchased by former sea captain Lemuel Moody. Moody, who had retired from active sailing after being captured by French privateers during the Quasi-War between the United States and France, was inspired by the flag system at Federal Hill in Baltimore. Moody sought to replicate the system in Portland, which was at the time the nation’s seventh largest port.

Constructed from Windham timber, the observatory served the city of Portland for more than 100 years, with Moody and his descendants communicating via semaphore with captains and ship owners who paid the $5 annual fee. Moody was able to spot the ships with his powerful telescope, which could identify incoming vessels up to 30 miles away.

The observatory has a replica of the telescope, a P&J Dolland Automatic Refracting Telescope at 65x magnification, on one of its floors. Nadeau said the replica was purchased by a docent on eBay, who initially got outbid by just 5 cents. However, the original seller later decided to donate the telescope to the observatory.

Nadeau described Moody as a man who was dedicated to the observatory, going up and down 4.4 million steps until his death in 1846 at the age of 79. Moody built his own house near the observatory on Munjoy Hill, with stables, a banquet hall, and a bowling alley. He was also an active member of the community, chairing a hospital commission, serving as quarantine officer and commissioner of shipwrecks, and the city’s first weatherman, recording detailed observations decades before the establishment of the National Weather Service.

The observatory has played host to many historical events and occurrences. In 1817, James Monroe spent the first Independence Day of his presidency watching the fireworks from atop the tower. In 1863, the observatory played a pivotal role in the pursuit of Confederate sailors who had stolen the gunship Caleb Cushing, and a few years later, Enoch Moody, Lemuel’s son, successfully saved it from the Great Fire of 1866. The efficiency of the building drove the success of Portland, which, for much of the 19th century, served as the main ice-free port for Montreal.

The building ceased to be an active observatory in 1923, as it was made obsolete by the two-way radio, and was donated to the city of Portland in the 1930s. The city secured $6,000 from the Works Progress Administration for renovations, and Nadeau noted there was a distinction between stained and unstained wood in the structure, with the former being part of the original structure. The observatory was named a National Historic Landmark in 2006, one year shy of its bicentennial.

During World War II, the observatory served as a watchtower for Portland Harbor. Nadeau said one of the men who served as part of the watch, Doug Johnson, currently serves as a docent, and is still sharp as ever, even as he turns 100 this year.

Blake said the historical society is focused on documenting the history of the New Gloucester area, with documents and artifacts stored in the affectionately named “history barn,” located on the same property as the meetinghouse and town hall. The barn, Blake said, opens to visitors on the morning of the first Saturday of each month, with the next event scheduled for May 2.

Nadeau will give another presentation on Wednesday, April 29, at Portland Public Library. The presentation will focus on the history of mapping in Portland.