In the 1800s, people called the steep valley of Connecticut’s Naugatuck River, “Brass Valley,” because from the time the world began running on steam and bearings, trolleys and soot, the Naugatuck Valley was the location of where most of the world’s brass manufacturing happened.

In 1802, two metalworking families joined forces to manufacture brass. Business soared during the War of 1812 with the demand for buttons, and soon brass parts became essential in the age of steam and electricity.

As large-scale brass manufacturing grew across Brass Valley, mill towns along the river, such as Torrington and Waterbury, developed into thriving cultural centers. In 2014 the last plant closed, and the tradition of soot-covered workers charging generations-old furnaces came to an end.

Author and photographer Emery Roth published a book “Brass Valley: The Fall of an American Industry” (Schiffer Books, 2015) and will present a slide talk about it at the Fairfield Museum on Wednesday. The “History Bites” lunchtime lecture takes place on March 20 at 12:30 p.m. and is open to the public. Roth will talk about how America’s industrial past has propelled his artistic explorations.

Roth and Lazlo Gyorsok began photographing abandoned factories but actually found themselves documenting the last working brass mills in the valley, places where workers still poured glowing metal and ran century-old machines.

“We had stepped into the past,” says Roth. “The production line had been a secret — men using ancient machines to make specification-critical, seamless tube for nuclear submarines. Photographing there for three years was the realization of an impossible dream and led to the publication of (the book).”

The talk is free for Museum members with a $5 suggested donation for non-members. Attendees should bring a bagged lunch. Beverages and dessert will be provided.

The Fairfield Museum & History Center and Museum Shop, located at 370 Beach Road, is open seven days a week, 10am-4pm. Members of the Museum and children under 5 are admitted free. For more information, call 203-259-1598 or visit Fairfieldhistory.org. The Fairfield Museum relies on funding from individuals, corporations and foundations.