Revisiting Riccioli’s free-fall calculations

Graney replies: Patrick Warren and Dietrich Leibfried raise interesting points about errors—both in Giovanni Battista Riccioli’s work and, unfortunately, in my article. In the latter case, Leibfried is certainly correct about the units on the axis. In fact, other Physics Today readers have called my attention to a number of typographical errors related to the plot and measurement values listed in the article. For example, the height of the Asinelli Tower according to Eleonora Bertacchini and coworkers (reference 15 in the article ) is 97.38 m, ¹ but in the article it is listed as 98.37 m. For typo-free (hopefully) plots and values, I refer readers to a full translation of Riccioli’s report on falling bodies. ²

No doubt Riccioli would understand all this. His Almagestum novum suffered from severe typos in places. For example, values labeled as being the radii of objects sometimes actually provided the diameters!