Almost everything about a historical image of Congress Avenue that dates back more than 100 years ago looked right to our readers.

Except the windmill that looms in the upper left corner.

Examining the details — while crowd-sourcing on social media at the same time — we determined the approximate date and location of the photo shoot. Then one reader struck gold on the question of where that windmill came from. Thank you, John Broderick, wherever you are. You win the gold star this week for historical research in the digital age.

Let’s retrace our steps.

An easy way to start: The 1888 state Capitol appears at the center of the image. Electric trolley cars follow tracks up the avenue toward the domed building. Another streetcar crosses the field of view at Sixth Street. So the photograph must have been taken after 1891, when electricity began to replace mule power for Austin mass transit.

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We also know right away that the photographer is located on or near Fifth Street, since we can see the crossing Sixth Street trolley in the near foreground, and the sign on the old Scarbrough & Hicks Building is on view to the left.

To explain the familiar Austin name, retailer Emerson Monroe Scarbrough moved into that spot from the 400 block of Congress Avenue in 1894. That store was replaced at the Sixth and Congress location in 1909 by a modern nine-story tower that was later refurbished in the Art Deco style that it still retains. E.M. Scarbrough & Sons department store closed its downtown location after a slow Christmas in 1982. The last Scarbrough’s location, the one on North Lamar Boulevard, was shuttered in December 2009.

So we know the image predates the 1909 Scarbrough Building.

Back to the avenue: The mostly brick facades of the businesses that line the sidewalks follow the ornate styles of the Victorian period, an exuberance crowned by the 1876 Travis County Courthouse seen just to the right of the Capitol. Sadly, that building was demolished in 1964 after years of abandonment and deterioration.

One can see the bricks that pave Congress in this image, so this must be before the modern, smooth paving efforts of 1905.

Getting closer: People in view walk or ride in horse-driven buggies. One early automobile model is parked — end-first parking! — on the left.

According to David’s Humphrey’s usually reliable “Austin: An Illustrated History,” the city’s first auto “chugged up Congress Avenue just after the turn of the century.”

So we can confidently date the image to the years between 1900 and 1905.

That conclusion left quizzical readers with the mystery of the rooftop windmill. Two of our favorite Twitter feeds — Traces of Texas (@TracesofTexas) and Austin Daily History (@austindailyhis1) — were the first to poll for solutions.

“It may be from a photo but it looks suspiciously like a lithograph print, possibly with some artistic license thrown in,” regular reader Bill Padgett comments. “I’ll ask my 101-year-old father-in-law when I see him tonight.”

“I’ve seen this windmill in several old photos of Austin,” Jeff Kerr, author of excellent books on early Austin history, writes. “It was even on a jigsaw puzzle I put together once. When the city was founded, there was a creek called Rio Bravo that ran south from where the Capitol is along Congress Avenue to around Sixth Street before turning east. There were also several springs on that side of Congress. Perhaps the windmill tapped into one of those water sources.”

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That leads us to the windmill question. Remember John Broderick? He consulted Newspapers.com and found an advertisement for G.C. Bengener and Bro., a retailer located on Congress Avenue that employed the slogan “The Cash Hardware Dealers. Sign of the Windmill.”

That ad copy came from the Austin Statesman on Nov. 26, 1897. Turns out that Bengener's hardware store sold windmills, too, and had been in business since 1878.

“This wide-awake and progressive firm, composed of George C. and L.R. Bengener, do an extensive business in hardware, with premises at 510 Congress Ave.,” reads an earlier article from March 22, 1894, that sounds more like more ad copy. “Their stock is well assorted and embraces a large variety. They make a specialty of builders’ hardware and fine tools: Buffalo scales, Morse elevators, Rambler bicycles, and are agents for the Aermotor windmill.”