218 Meteorological Phenomena in 



is stormy, and roars as in an empty street. The Berlin newspapers 

 have for that reason no influence on the wagers as to when the 

 Neva will rise, for the thaw-wind outruns the posts. On account of 

 the impetuosity with which the south wind presses forward into 

 higher latitudes, it loses, by constantly-renewed precipitation, some 

 of its moisture, especially on the southern declivities of mountains. 

 Besides this precipitation there is another of an entirely different kind, 

 which takes place when two opposing currents meet, In Italy the 

 rule is,— 



" Non fu pioggia senza vento, 

 Non fu vento senz' aqua." 



And in the south of France they say, — 



" Quand le soleil est joint au vent 

 On voit en l'air pleuvoir souvent." 



This precipitation happens in two cases ; the one when the warm 

 current has forced itself through the cold one, and vice versa. The 

 most frequent storms, drizzling showers, and raging snow-storms, 

 come with a west wind. But this kind of weather lasts, as they say, 

 only a span long. It cools the air, and a cloudless succeeds to an 

 overcast sky ; it is the transition from bad weather to good. The 

 transition in this case takes place quickly, because the heavier cold 

 wind forces itself easily into the place occupied by the warm wind. 

 And on account of the cold wind being heavier than the warm wind 

 which preceded it, the barometer rises during this kind of weather, 

 and then wo say — the barometer is on the rise, — it will be fine wea- 

 ther. Thus, too, if the cold wind forces itself in below, as it does 

 into a warm room when the doors are open, it blows before it the 

 clouds which it forms in its progress, and which darken the air as 

 it advances through the sky. Now, in proportion as this cold 

 lower current of wind is more or less directly opposed to the warm 

 current, which until then had prevailed, there takes place between 

 them in summer, the peculiar stillness which we term oppressive 

 air. The expression, " the storm comes up against the wind," finds 

 its explanation in the proverb itself. Just in proportion, then, as 

 the wind gains in strength, the storm more quickly forms ; thence 

 the sudden obscuration of the sky which takes place without any 

 previous warning. The rain, on the other hand, which the south 

 wind occasions, when it drives away the north wind, draws near 

 with a south-east and south wind. It first falls on the hills, and 

 then descends below, causing the barometer to fall, because the wind 

 which follows it is lighter ; it is the transition from fine weather to 

 cloudy. " The barometer is falling, it will be bad weather," we 

 say, — the north-cast wind has gone round to south-east ; it will soon 

 be south-west. At what point in the scale the barometer stands, 

 signifies little, the principal thing is, if it be on the rise or the fall. 

 Snow after severe cold, passing into thaw, storms which come with 



