Fluting Plan of the Ionic and Corinthian Column
The Ionic column has a less diminished shaft and a smaller parabolic curve than the Doric. It is, like the Doric, channeled; the flutings, which are 24 in number, are separated by annulets, and are therefore narrower, but at the same time deeper, than the Doric, and are terminated at the top and bottom by the final curvature.
A. Rosengarten, W. Collett-Sandars A Handbook of Architectural Styles (New York, NY: Charles Scribner's Sons, 1895)
Courtesy the private collection of Roy Winkelman