ITS CAUSE 15 



the formation of any definite figure. So in the atmo- 8 

 sphere the same thing happens ; when it is stationary, 

 it may receive a pattern ; when it rushes in rapid 

 motion, it evades all control, warding off every 

 blow and every form as it approaches. When these 

 crowns, of which I have spoken, have disappeared 

 uniformly on all sides, and vanished in their own 

 tracks, it is an indication of equilibrium in the atmo 

 sphere : there is perfect quietness and you may then 9 

 look out for rain. When they break up at one side, 

 it means wind in that quarter. If they burst at 

 several points, a storm is brewing. The reason of 

 this may be gathered from the explanations I have 

 now given. If the ring fade all round, it is evident 

 that the atmosphere is equable, and therefore calm. 

 But if it is broken through on one side, evidently there 

 must be an inclination of the air in that direction : 

 hence that quarter will produce wind. But when the 

 halo is rent and torn on all sides, plainly an attack is 

 being made on it from several quarters at once, and 

 a disquieted atmosphere is assailing it on this side 

 and on that. So this disturbance of the heavens, 10 

 the repeated effort and striving in all directions, 

 betokens evidently that a storm is coming up with 

 sudden shiftings of the wind. 



These crowns may be observed generally by 

 night round the moon and other stars, but very 

 seldom by day ; in fact, so rarely in the latter case, 

 that certain of the Greeks have denied that they 

 appear at all by day. But history proves that 

 they do. The cause of the infrequency of their 

 appearance by day is that the sun s light is stronger 

 then, and the atmosphere itself when stirred and 

 warmed by it is less dense. The moon s power, on 

 the other hand, is feebler, and is therefore more 



