The blast of a fire whistle echoed through downtown Mystic, setting in motion an event the village had long awaited.

On the Groton side, a delegation of officials set out from the Mystic Hook and Ladder Co., while in Stonington, another contingent left the B.F. Hoxie Engine Co. The two groups, sporting silk hats and led by brass bands, were soon on Main Street, facing each other on opposite approaches to the Mystic River Bridge.

With a crowd on hand and car horns blowing, the Stonington group watched as the lift span, decked with flags and bunting, rose perpendicular to the street. The Groton officials saw two high counterweights descend until they almost touched the ground.

On July 19, 1922, a hundred years ago this coming week, Mystic celebrated the opening of its new bridge. A century later, a yearlong anniversary observance is underway.

During the time in between, the bridge has gone from modern marvel to part of the landscape. It withstood hurricanes, admitted the arriving whaleship Charles W. Morgan, and played itself in the movie “Mystic Pizza.” It’s the hinge connecting the village’s two halves.

Though it may seem as if it’s always been there, the bridge had a beginning like anything else. Here’s the story of how a southeastern Connecticut landmark came to be.

* * *

Mystic’s previous bridge opening wasn’t exactly festive. On Tuesday, Sept. 20, 1904, officials announced that a new steel swing bridge would be ready for use two days hence.

“There will be no celebrations on Thursday,” The Day noted, “for the townspeople believe they have nothing to enthuse about.”

Why that was isn’t clear, but they enthused even less when the bridge opened a day early.

“Much inconvenience was caused (to) persons who walked and drove to the temporary bridge ... only to find the way blocked,” The Day said.

The swing bridge was a leap into the future because it did something its 1866 iron predecessor couldn’t: carry trolley cars. The Groton & Stonington Street Railway Co. paid half the cost of the bridge, part of a new streetcar line from Groton to Westerly.

But the bridge, with trademark green paint, soon lived up to its cheerless welcome. The foundations settled unevenly, and the draw would freeze in the open position, causing exasperating travel delays.

Another problem was that the whole thing pivoted on a center pier in the Mystic River, leaving two narrow channels that were hard to navigate.

By 1919, after just 15 years, officials were pursuing a replacement, and the timing was perfect: Their new bridge had just been invented.

* * *

Bascule spans, according to a 1926 book called “Movable Bridges,” are in the basic sense, “those in which one end rises as the other falls.” At the time, many designs had been patented, “and some are vigorously promoted by the patentees.”

Several engineers were prolific at patenting bascules. William Scherzer invented the “rolling-lift” type, of which the Niantic railroad bridge was an example. Joseph Strauss’ “heel-trunnion” design was used for the Thames River railroad bridge.

Thomas Ellis Brown wasn’t a bridge innovator at first. As chief engineer of the Otis Elevator Co., he brought elevators to the Eiffel Tower and New York’s Woolworth Building, then the world’s tallest. But a bridge design competition in Brooklyn, N.Y., drew his attention in 1896, and he and his son went on to hold a dozen patents for bascule designs.

In late 1916, Brown submitted his latest idea to the U.S. Patent Office. In five pages, he described a problem and proposed a solution.

Under existing designs for bascule bridges balanced by overhead counterweights, if the bridge rose 90 degrees, the beams holding the counterweights had to stay parallel to the span and descend 90 degrees to maintain balance. This posed design difficulties that increased cost.

Brown’s proposal kept both sides balanced despite the beams moving through a smaller angle than the bridge.

Analyzing the idea later, a civil engineering eminence named J.A.L. Waddell wrote that Brown had “succeeded in producing the most economic bascule with overhead counterweight yet evolved.”

Brown was awarded Patent No. 1,270,925 on July 2, 1918. That was just about when Mystic’s patience with its balky swing bridge was reaching its limit.

* * *

The impact of the swing bridge’s problems extended beyond Mystic. Main Street was part of Route 1, the busiest of Connecticut’s 14 major roads. These had been designated in 1907 as “trunk lines” to be improved by the state in response to increasing auto traffic.

The state highway department could have opted for a better swing bridge, but that wouldn’t have widened the river channel. It looked into a vertical-lift bridge, but the needed height clearance was impractical.

That left some kind of bascule, and officials chose the Brown Balance Beam design, based on the inventor’s 1918 patent. No bridge of this type had yet been built.

Beams holding towering concrete counterweights would drop just 69 degrees to lift the draw fully vertical. There was another new feature: Powered by electric motors, the bridge would move by means of two operating wheels above the roadway, called “bull wheels,” that also locked the bridge in place when closed.

The details emerged in a series of drawings in 1920 with Waddell serving as consulting engineer and Brown as advisory engineer. Construction began in July 1921.

The first order of business was the creation of a temporary bridge to hold Mystic together through the inconvenience of the next 12 months. It was built north of the swing bridge and connected Gravel Street with Holmes Street.

Then the swing bridge was dismantled, and for a few days the occasional daredevil tried to keep using it “although nothing remains of the old bridge but a skeleton,” The Day said. “Several who tried to cross on the girders found their courage not so great as they imagined.”

For the rest of 1921 and the winter of 1922, the site was a warren of derricks and cofferdams as the J.E. Fitzgerald Construction Co. of New London, the general contractor, worked under the Mystic River to clear out old foundations and build stronger ones.

On Feb. 23, the center pier of the swing bridge was detonated with explosives. That left a channel 75 feet wide.

By early April, the substructure was complete: an abutment on each side, and three pairs of piers. All that was needed was a bridge to put on them.

* * *

Max Bendett, a downtown merchant, couldn’t imagine how long construction might last. Just before Christmas, he had bet A.R. Collier, the project’s resident engineer, a box of cigars that the new bridge couldn’t be crossed on foot by May 15.

As April dawned, Bendett seemed on track to win his bet. There was nothing but empty space where the bridge was supposed to be. But that wasn’t because the superstructure hadn’t been built. It was just built somewhere else.

The American Bridge Co., a U.S. Steel subsidiary, held the contract for the superstructure and had been working for months at its headquarters near Pittsburgh. The firm had prefabricated steel parts ready to ship to Mystic as soon as the piers were ready. Assembling them didn’t take long.

On May 15, with the bridge quickly taking shape, Collier summoned Bendett, carefully walked him across, then collected his cigars.

Engineers wanted the bridge open by the Fourth of July, and they didn’t miss by much. On July 10 the roadway was cleared of debris, and a car carrying Thomas Brown became the first automobile to make the crossing.

Brown was staying in New London and still innovating. On April 29 he had filed his final patent application, which improved on his counterweight idea and included aspects of the Mystic design, including the bull wheels. He received his last patent, No. 1,519,189, posthumously in 1924.

Two days after Brown’s trip across the river, the bridge quietly opened to traffic.

* * *

That did nothing to dampen the celebration on July 19, by which point travelers had been using the bridge for a week. That day, trolleys began crossing, and demolition started on the temporary bridge.

A ceremony was in order to make it all official.

“It is hardly to be wondered at that the opening of the bridge should be celebrated,” The Day editorialized. “It means a great deal to everybody and the event is one that should receive all the recognition possible.”

That evening, as the crowd looked on, the lift span hung in the air for a moment as the silk-hatted Groton and Stonington officials waited on either side. Then it descended, allowing them to meet on the bridge.

They were greeted by R.L. Saunders, the deputy state highway commissioner, who formally turned over the bridge to the towns.

The two halves of Mystic were again firmly joined, for the next century and beyond.

Editor’s note: This story was drawn from many sources, including the state Department of Transportation, the University of Connecticut, the files of Groton Town Historian Jim Streeter and the archives of The Day and the Westerly Sun.

j.ruddy@theday.com