Of the more than 4,000 carousels built in U.S. during their heyday in the late 19th and early 20th centuries, it is estimated that fewer than 150 survive. One of them is at the Volo Auto Museum, located along Route 120 just east of the McHenry County line. The eclectic way-stop for seemingly all things on wheels added something else this winter that spins round and round: a 1920s Allan Herschell Co.