234 VARIETIES OP WEATHER. CHAP. . 



Atmosphere, particularly when accompanied by 

 Westerly Breezes ; which though they do not 

 vary directly as the Sun's altitude, yet seem, in 

 some measure, to keep pace with it. and a calm 

 succeeds in the evening. 



This order and distribution of the clouds 

 happens with different Winds, and different 

 states of the Thermometer; for it is not confined 

 to hybernal frost, nor to the heat of the Dog 

 Star. When it takes place, however, the 

 mercury in the Barometer is seldom very low or 

 variable. Indeed it may be said, in general, to 

 be conjoined with a mean state of that instru- 

 ment. This weather is of longer or shorter 

 continuance, as may happen : the appearance of 

 cirrus and cirrostratus, and above all, the fleecy 

 and irregular look of the cumuli, with sudden 

 variations in temperature and pressure, indicate 

 a change. Sometimes these appearances soon 

 subside, and the same weather returns. The 

 cumuli, too, occasionally become rocklike, ap- 

 proach to cumulostratus, and spread, without 

 ending in llain ; but these are exceptions to the 

 general rule. When to such a continuance of 

 regular nimbification, as described above, cir- 

 rocumulus supervenes, an increased warmth 

 often follows, and frequently without Rain. 



