8 - Continued observations on the earthquakes that have been experienced for some time (1756)

Summary

EDITOR'S INTRODUCTION

Kant's third and final essay on earthquakes was published in the 10 and 17 April issues of the Wöchentliche Königsbergische Frag- und Anzeigungs-Nachrichten and continues the reflections presented in the previous two essays. Kant's primary concern in this essay is to refute various competing opinions about earthquakes, specifically, those by Gottfried Profe and Pierre Bouguer. His main objection to Profe, who claims that the alignment of the planets was responsible for the Lisbon earthquake, and to Bouguer, who agrees with an unnamed Peruvian author that the Moon could bear some responsibility for this event, is that if one calculates the actual gravitational effect that either the planets, fully aligned, or the Moon by itself would have, the effect would be minuscule and certainly much too small to be a significant cause of such a large effect. Moreover, Kant notes, a report by Gassendi suggested that a rare conjunction of the three outer planets, which had occurred in 1604, resulted in no significant earthquakes, thus contradicting Profe's theory. Kant concludes his treatment of earthquakes with a brief reiteration of the main contours of his theory.