Diatribe de Progidiosis Crucibus

A second edition of the work was published in Rome in 1666 and a German translation appeared in Gaspar Schott's Joco-seriorum naturae et artis (Würzburg, 1666).

[4]: 25  Between August and October 1660, Kircher travelled to the hamlets of Somma and Ottaviano to look for primary evidence himself, and also read accounts from other witnesses in southern Italy.

[2]: 233–4  The explanation for the cross-shaped marks, he concluded, was that fine ash and moisture had settled on cloth, taking cruciform shape defined by the weave itself.

[3] Kircher noted that the crosses had been seen on linen cloth but not on garments of wool, and that they had appeared only under certain specific conditions of temperature and moisture,[2]: 233–4  causing "guttulae nitrosae" (nitrous drops) to form on the surface.

Before publication in 1661, Kircher added a discussion about the appearance of crosses on fruit and meat, arguing that, like linen, these were fibrous materials capable of producing the same effect on their surfaces.

[3] The work was widely disparaged, and in 1677, Gioseffo Petrucci published Prodromo apologetico alli studi chircheriani[12] which sought to defend Kircher against those who thought his explanation of the phenomenon was too credulous.