At intervals, walkways interrupt the stalls, sloping up from the sidewalk behind the cows to the area in front of them. Behind the rear quarters of the cows is the gutter, where the pee splashes, and the cow pies mostly fall, and then the walkway from which the barn hands clean the gutter and do the milking. Finally come the thick whitewashed walls.

Jackie follows the walkway clockwise. Twenty-one windows set close together all the way around; they make the cowbarn a light and airy place. There are also five doors. The people entrance, that goes through the washroom with its sinks and hoses to meet the sidewalk from the milk house. The Dutch door wide enough for a cow to go through into the passageway to the side barn. The double doors that reach from walkway to ceiling, which open into the vestibule to the barnyard and are flung wide to let the cows in for milking. the cows crowd through these, led by the head cow, and mill and stamp and find their stalls. The fourth is the manure trolley door. The trolley is pulled or pushed on its overhead track through this exit and its load dumped onto the manure pile at the edge of the barnyard. The final door, again cow-sized, opens onto the north barnyard which is flanked by the horsebarn and calfbarn.

There’s an interesting feature in the cowbarn that is Grampa’s invention. In between almost every window, up against the ceiling, is a hole about a foot square with a sliding wooden shutter. On the outside of the cowbarn, down between the windows, each square has its corresponding screened square. The two have a passage between them through the thick walls; they form a kind of periscope for air, and are part of Grampa’s ventilation system for keeping the barn cool in summer and warm in winter. The other part of the system is the two tall wooden shafts that run alongside the silo, up through the upper barn to the fans on the roof. When the ventilator fans turn, they pull hot air up from the center of the cowbarn to the roof.

Then to replace the hot air, cooler air enters through the little low outside windows and flows up the wall passages into the barn, entering at the ceiling-level square. The cool air sinks to the floor. The hot air, meanwhile, is flowing toward the center of the barn and up to the big ventilator shafts to the outside. There’s a continual current of warm leaving the top, and cool coming in the bottom.

It’s one of Daddy’s favorite tricks, when visitors come to the round barn, to demonstrate these ventilators. He takes his handkerchief and holds it under the shaft, and the wind going up nearly pulls it out of his hand. With this system it takes a terrible heat wave to make the barn anything but pleasant in the summer. In the winter, the shutters are closed and the cow’s bodies heat the barn; the thick walls hold in the heat. The roof fans need change the air only once in a while.

Sometimes a sparrow manages to get into one of the ventilating passages in the outside wall and is trapped. Jackie or Craig discovers it beating its wings against the screening, and reports it. Then a barn hand loosens the screening and lifts the exhausted little body out.

Jackie goes through the washroom entrance to the outside and checks to see if there are any stray sparrows in a ventilating window. She follows the narrow concrete sidewalk around the barn to the horseyard. Because the barn is built on a slight slope, the sidewalk gets gradually lower while the windows remain the same height. By the time she gets beyond the horseyard, the windows are almost to high to look into. On the barnyard side, she knows, they’ll be far too high.

There are no sparrows. And she has plenty of material for extra credit. She must remember to list “The Aims” when she describes the upper barn, but she knows these by heart. And at the end, to say how impressive the barn is, and that people often drive out on Sundays to see it and watch the milking. A good last line can be, “W.J. Dougan’s round barn is a landmark in southern Wisconsin.”

She goes into the big house to get a sugar cookie from Grama, and to tell her about the essay, before riding her bike back up to Chez Nous.