In the last few weeks, 10 of the cast-iron lampposts in Madison Square Park in Manhattan have grown a bit taller. Micah Silver was responsible. He is the one who put the little thingamajigs on them, on the tippy-tops. The finials, to those in the know.

Mr. Silver is an artist and a composer who is preparing an installation that is scheduled to go up in the park 10 months from now. It will have a visual component — pieces of fabric that he will design and place around the park — but it will really involve creating something that is heard, not seen: the sound that air makes as it rushes between the trees, over the benches and around the lampposts.

The fabric pieces are meant to reproduce the effects of the air — very low-tech. To know where to set them up in February, he decided to record the wind. To do that, he devised the thingamajigs — very high-tech. They are made of plastic. They are black, just like the lampposts. They look like two cups, stuck together, from an anemometer, a whirling instrument that measures the speed of the wind.

“The idea is, wow, there’s this other way to look at the park: airflow,” Mr. Silver said. “It’s not about air quality in terms of pollution; it’s about air forms.” The devices are “not exactly artwork,” he said. They are “just going to be there,” taking readings with sensors and transmitting the readings wirelessly. Unobtrusively. Unnoticed.