of Grandi's series, it is surprising that Varignon's report does not even mention Leibniz's earlier work. But most of the Précautions was written in October 1712, while Varignon was away from Paris. The Abbé Poignard's 1704 book on magic squares, Traité des Quarrés sublimes, had become a popular subject around the Academy, and the second revised and expanded edition weighed in at 336 pages. To make the time to read the Traité, Varignon had to escape to the countryside for nearly two months, where he wrote on the topic of Grandi's series in relative isolation. Upon returning to Paris and checking in at the Academy, Varignon soon discovered that the great Leibniz had ruled in favor of Grandi. Having been separated from his sources, Varignon still had to revise his paper by looking up and including the citation to Jacob Bernoulli. Rather than also take Leibniz's work into account, Varignon explains in a postscript to his report that the citation was the only revision he had made in Paris, and that if other research on the topic arose, his thoughts on it would have to wait for a future report. (Letters between Varignon and Leibniz…) In the 1751 Encyclopédie, Jean le Rond d'Alembert echoes the view that Grandi's reasoning based on division had been refuted by Varignon in 1715. (Actually, d'Alembert attributes the problem to "Guido Ubaldus", an error that is still occasionally propagated today.) Riccati and Bougainville In a 1715 letter to Jacopo Riccati, Leibniz mentioned the question of Grandi's series and advertised his own solution in the Acta Eruditorum. Later, Riccati would criticize Grandi's argument in his 1754 Saggio intorno al sistema dell'universo, saying that it causes contradictions. He argues that one could just as well write but that this series has "the same quantity of zeroes" as Grandi's series. These zeroes lack any evanescent character of n, as Riccati points out that the equality is guaranteed by He concludes that the fundamental mistake is in using a divergent series to begin with: Another 1754 publication also criticized Grandi's series on the basis of its collapse to 0. Louis Antoine de Bougainville briefly treats the series in his acclaimed 1754 textbook Traité du calcul intégral. He explains that a series is "true" if its sum is equal to the expression from which is expanded; otherwise it is "false". Thus Grandi's series is false because and yet . Euler