On my way from Burlington Junction, Missouri, where my great grandpa Spangler died with five others when a tornado in 1903 flattened the Masonic Lodge they’d taken refuge in, and Palmyra, Nebraska, where my grandpa Spangler was born in 1897 in a sod house, I crossed the Missouri River and passed through Nebraska City, population 7,289. Stopping wasn’t my plan, but when I saw a pristine silver windmill standing proudly at the eastern edge of Main Street, curiosity stomped its foot and demanded satisfaction.

Surely, the Spangler homesteads in both states depended on this prairie icon to pump their water. Rare is the farm I’ve passed that doesn’t have a windmill in its dooryard, or at least its four-legged galvanized skeleton with a battered TV antenna taking the place of the wind wheel since supplanted by electricity. So why was there a pristine silver wheel spinning in downtown Nebraska City?

Thick black capitals on its broad sheet-metal tail said ELI, small capitals above and below read “Kregel Windmill Co.” and “Nebraska City, Neb.” And across the street was the factory. Peering in the windows revealed thick belts connecting the overhead drive system to robust cast iron machines. Raw materials rested in neat piles. Finished parts filled wooden bins. It looked as though the workers had gone to lunch, for it was that time this sunny day in June 2014. The door was locked, but a small sign by it said tours of the Kregel Windmill Factory Museum were available next door.

My $5 admission started a one-on-one tour with Dean Shissler. A history major at nearby Peru State College, an internship led to his becoming the museum’s only full time employee. Instead of a practiced oration that followed a prescribed path through the museum, curiosity led a wandering Q&A conversation.

ELI was the windmill’s brand name. George F. Kregel founded the company in 1879, and it operated in this facility between 1903 and 1991, when his son, Art, closed the doors. “It was named a National Historic Site in 1994, so we couldn’t change anything,” said Dean. It took nearly three years to build a steel building around the original factory that incorporated the HVAC system to preserve the original wooden structure and its contents. Looking at it inside and out, you’d never know it.

The factory exists today as it did in 1939, Dean said, when two electric motors replaced the single-cylinder putt-putt engine that turned all the machines through the overhead drive and thick buffalo hide belts. The shear, hack saw, drill press and other cast iron behemoths still work, but that rarely happens “because OSHA knows about us.” Video kiosks demonstrate their operation on demand.

Flipping switches, Dean’s demonstration of the museum’s dramatic lighting concluded with the gloom cast by 11 small, clear bulbs connected to their original knob and tube wiring. It’s a 12-volt system now, he said, but the lumens replicate the workers’ 1939 environment.

More than 81,000 pages of company records still reside in the front corner office. The first ledger is dated 1879; that year they made 16 windmills, all wood, that sold for $90 to $100, depending on the size. When not talking with visitors, Dean is transcribing them for a digital archive. It is slow going, he said. The pages are filled with neat Palmer penmanship in spidery black ink. “On a good day, I can complete two pages.”

Original parts to make a number of 1920-era windmills fill the building. Production stopped with the outbreak of World War II. Metal windmills were not a wartime priority, and Art Kregel often said, “If I’d made one more windmill, I’d go broke,” Dean recounted. The company, whose only heat came from a single potbelly stove, survived until 1991 by repairing the mills already made and other projects.

Not long ago, someone in Denver found the tail of a 131-year-old all-wood Kregel, said Dean, when I asked about the 16-foot wood wheel. It was a replica; like the originals, it was made of ash. “They made mills of wood and metal for a while before going to steel.”

Manipulating a working model, Dean explained the elegantly simple design. It was a 1:1 direct-drive system; “One full rotation of the wheel is one full pump motion.” A crank plate turns the wheel’s rotation into a vertical 2-foot stroke that raised and lowered the pump’s check-valve piston.

An articulated tail vane regulates the wheel speed by controlling its angle of incidence to the wind. “The stronger the wind the more the tail pulls the wheel to the side. At 35-40 mph, the vane is parallel to the wheel, locking it in place and applying a brake to the crank plate. When the wind slows, the weight of the vane pulls on this drag line to open the hinge and releases the head, unless you lock it manually.”

Most windmills today, like the Aermotor, are geared, Dean said, which is why they have smaller wheels. A 4-5 mph wind will start them turning. “It takes almost twice that to start an ELI, but in Nebraska, we don’t lack for wind.”

Introduced in 1888, Aermotor delivers more lifting power through 3:1 gearing, three revolutions of the wheel equals one pump stroke. Born in Iowa, the company went through several owners before finding a home in San Angelo, Texas.

“We have about a hundred of them, and we’re adding more as the years go by,” said Chris Gentry, who was a student of mine at Missouri Military Academy in the 1980s. He runs grass-fed cattle on 50,000 acres in western Nebraska, an operation the family started in the 1890s with 5,000 acres. Given their remote locations, electric pumps aren’t really an option; windmills are reliable and relatively inexpensive to buy and maintain. “We’ve been using them since 1900. We were green before green was cool.”

Curiosity sated, on my way to Palmyra it occurred to me that windmills are, in a way, related to things aeronautical. Like airplanes, succeeding generations do not replace their evolutionary predecessors, they work alongside and with each other. Windmills, with their century-old technology, still pump water while wind turbines, with slender blades like a sailplane’s wings, face the into the same wind as they work.