It brought a breath of fresh air.

That was the achievement of a remarkable agricultural invention called the slotted inlet ventilation, dreamed up by Cornell University Professor William F. Millier. Now the 50th anniversary of the discovery is to be celebrated by ASAE, formerly known as the American Society of Agricultural Engineers, an international society for engineering in agricultural, food and biological systems, and the Cornell Department of Agricultural and Biological Engineering at a symposium Nov. 23 from 3 to 5 p.m. in 125 Riley-Robb Hall.

"Few advances in animal housing have had as important an impact," says Norman Scott, Cornell professor of agricultural engineering. Because effective air inlets are essential to farm animal ventilation, the development of mechanical ventilation methods was a crucial step in the evolution of modern animal agriculture, keeping animals healthy.

In recognition of the importance of the slotted inlet, invented by Millier, now professor emeritus of agricultural and biological engineering at Cornell, an ASAE historical marker will be placed on Riley-Robb Hall. Millier will deliver a talk at the symposium "How the Slot Got Slit."

In 1948 Millier, then a graduate student working under Cornell Professor Clesson Turner, tested and published the concept of the slotted inlet, a simple air-inlet system. The inlet is part of the building structure, providing uniform distribution of air pressure, inducing air mixing and preventing stale-air zones throughout the building. After its introduction in a Dryden, N.Y., dairy barn, the slotted inlet was adopted throughout the world and became the most widely used air-inlet control mechanism for mechanically ventilated agricultural buildings.

The symposium also will include talks by Louis Albright, Cornell professor of agricultural engineering, on "Inlets: The Link Between Animals and Fans"; John Ogilvie, University of Guelph, Canada, on "Design Standard: The Bridge from Theory to Practice"; Michael Kelley, Scottish Agricultural College, Scotland, on "A Room Full of Holes, You Must Be Kidding!"; and the presentation of the plaque by Melissa Moore, ASAE executive vice president.

Following the symposium, a reception will be held in 400 Riley-Robb Hall.