44 EFFECTS OF FORESTS ON HUMIDITY. 



mell into the house. Not a moment too soon. The hea-vens grew 

 black as ink ; the birds flew in terror to some cover, filling the air 

 with their screams j the wind swept past with a low portentous sigh : 

 and we had hardly our goods and ourselves under shelter, and the 

 doors and windows secured, when the storm was upon us, and raging 

 in mad tumult without. 



" The air becomes thick with sand, and lurid, like the yellowest of 

 London fogs ; the wind rises into fury, and the dust is driven hither 

 and thither as by a whirlwind. The sun seems blotted out, and in 

 the appalling darkness you see the lightning play and dart, and zig- 

 zag from heaven to earth, without one moment's intermission. The 

 thunder comes, not in distinct explosions, and then a pause, but in 

 one continuous roll of terrific reverberating noise, while the rain 

 descends with an abandon quite in keeping with the other forces of 

 the storm. It generally comes in horizontal sheets of water instead 

 of drops, and is driven by the mighty wind as you have seen seaspray 

 driven from the wave-tops in showers of foam. A storm like this is 

 a magnificent spectacle, and its efiects are delicious. In a wonder- 

 fully short time the conflict ceases — the thunder roUs away into the 

 distance, the wind is hushed, the sim shines out, and Nature, though 

 tearful, looks happy and refreshed. Everything literally rejoices on 

 every side ; the air feels cool and light, and for some days there is 

 pleasure in existence. 



" Our little ffete was spoiled ; but when the war without ceased, we 

 made up by doing what we could for the pleasure of our guests 

 within, and aU is well that ends well." 



I design not to convey the idea that the moisture thus precipitated 

 had been passed into the atmosphere by the foliage of a forest • I 

 find no indication that a forest was there — it is the precipitation 

 occasioned by the reduction of temperature alone which I seek to 

 illustrate. 



Previous to such a downpour of rain the heavens were perfectly 

 clear, without a cloud to be seen ; yet there, it may be, the whole of 

 that moisture was suspended, dissolved in the air. The rain-cloud 

 may have appeared to proceed from beyond the horizon, and to come 

 thence, advancing onwards with resistless force, borne forwards by 

 the gust of wind, more like a tornado than aught else ; but there are 

 reasons, and these satisfactory ones, to warrant the conclusion that 

 the cloud had not been blown thither by the blast, but had been 

 formed at the various points of its advance, by the wind suddenly 

 cooling down the air below a temperature at which it could hold the 



