A very ancient belief, still commonly held at Cumana, Acapulco and Lima, establishes a perceptible connection between earthquakes and the state of the atmosphere that precedes these phenomena. On the coasts of New Andalusia people are alarmed when, in excessively hot weather and after long droughts, the breeze suddenly drops and the clear, cloudless sky turns reddish near the horizon. However, this way of predicting earthquakes is very uncertain, for when we gather together all the meteorological variations in times of earthquakes we find that violent shocks take place equally in dry and wet weather,