246 SEE— TEMPERATURE, SECULAR COOLING 



[April 20, 



and the winds must cease before dawn, and at daybreak, when the cold 

 causes a stillness; for necessarily the stillness in most cases comes to pass, 

 just as was also said before, because it is a reflex of the blast going within 

 the earth, and happens especially before the greatest earthquakes ; the blast 

 of vapor is not much scattered, either that without or that within the earth, 

 but borne along its course becomes at daybreak necessarily most violent. 



" The cold comes to pass on account of the exhalation of the vapor circu- 

 lating within, with all the heat naturally contained in it. If the winds do 

 not seem to be warm it is because they move the air filled with cold vapor 

 and considerable steam, just as in the case of the breath exhaled from the 

 mouth; in fact this vapor is but slightly warm, as when we breathe; yet on 

 account of the small amount of the air, the heat of it is not so evident; 

 but further away the breath is cold from the same cause that the winds are. 



" From the time that this force enters within the earth, the flowing away 

 of the vapor combined with the moisture makes the cold, in places where this 

 phenomenon is encountered. This is also the cause which ordinarily makes 

 a sign before earthquakes ; for whether by day, or a little after sunset, when 

 the sky is clear, a faint cloud appears spreading and lengthening itself out, 

 as a fine line perfectly straight, the blast of wind quieting down on account 

 of the setting (of the sun). Whence similar phenomena come to pass also 

 in the sea, about the shores ; and especially whenever it is thrown into 

 billowy waves, exceedingly violent and irregular, breakers at the beach are 

 produced ; but whenever a calm arises, because the breaking of the surface 

 is very slight, the waves are small and regular, 



" Accordingly that which the sea does around the land, the wind does 

 about the dark clouds of vapor in the air. So that whenever the wind calms 

 down, the cloud which remains is exactly a straight line and very tenuous, 

 as if it were a mere wave of diffuse air. 



" On account of these things therefore an earthquake is sometimes pro- 

 duced during the eclipses of the moon; for whenever the closing up of the 

 earth between the sun and moon is near at hand, and the light is not yet 

 indeed altogether gone, and the heat from the sun is still in the air, but 

 already languishing, a calm arises by the wind suddenly whirling about and 

 throwing itself in the earth, which produces the earthquake before eclipses ; 

 for the winds often arise before eclipses, winds at nightfall before eclipses 

 at midnight, and winds at midnight before those at dawn. And this comes 

 to pass on account of extinguishing the heat from the moon, whenever the 

 event is already near; in which development the eclipse consists. That which 

 holds the air and calms it having disappeared, it is agitated anew, and a 

 blast of wind arises late in the evening previous to the eclipse. 



" But whenever a powerful earthquake occurs it neither ceases immedi- 

 ately nor with a single disturbance; but sometimes it shakes for about forty 

 days; upwards of one and even two years is indicated at certain places. The 

 cause of the violence is the greatness and fullness of the blast of vapor, and 

 the forms of the places from which it flows; that which it strikes against, 

 but does not easily penetrate, shakes most; and it necessarily agitates in the 

 narrow places, just as in the case of obstructed water which is not able to 

 pass through. Wherefore just as in the body the inflamed throbbings do 



