198 INFLUENCE OF PRECIPITATION. 
Total Climatic Influence of the Forest. 
Aside from the question of local disturbances and their 
compensations, it does not seem probable that the forests sensi- 
bly affect the general mean of atmospheric temperature of the 
globe, or the total quantity of precipitation, or eyen that they 
had this influence when their extent was vastly greater than at 
present. The waters cover about three-fourths of the face of 
the earth, and if we deduct the frozen zones, the peaks and 
crests of lofty mountains and their craggy slopes, the Sahara 
and other great African and Asiatic deserts, and all such other 
portions of the solid surface as are permanently unfit for the 
growth of weod, we shall find that probably not one-tenth of 
the total superficies of our planet was ever, at any one time in 
and are probably erroneous. See Forssac, Météorologie, German translation, 
pp. 634-639. 
It certainly sometimes rains briskly at Cairo, but evaporation is exceedingly 
rapid in Egypt—as any one who ever saw a Fellah woman wash a napkin in 
the Nile, and dry it by shaking it a few moments in the air, can testify ; and a 
heap of grain, wet a few inches below the surface, would probably dry again 
without injury. At any rate, the Egyptian Government often has vast quan- 
tities of wheat stored at Boulak in uncovered yards through the winter, though 
it must be admitted that the slovenliness and want of foresight in Oriental 
life, public and private, are such that we cannot infer the safety of any practice 
followed in the East merely from its long continuance. 
Grain, however, may be long kept in the open air in climates much less dry 
than that of Egypt, without injury, except to the superficial layers ; for mois- 
ture does not penetrate to a great depth in a heap of grain once well dried and 
kept well aired. When Louis IX. was making his preparations for his cam- 
paign in the Hast, he had large quantities of wine and grain purchased in the 
Island of Cyprus, and stored up for two years to await his arrival. ‘ When 
we were come to Cyprus,” says Joinville, Histoire de Saint Louis, $$ 72. 73, 
““ we found there greate foison of the Kynge’s purveyance. . . The wheate 
and the barley they had piled up in greate heapes in the feeldes, and to looke 
vpon, they were like ynto mountaynes; for the raine, the whyche hadde 
beaten vpon the wheate now a longe whyle, had made it to sproute on the 
toppe, so that it seemed as greene grasse. And whanne they were mynded to 
carrie it to Hgypte, they brake that sod of greene herbe. and dyd finde under 
the same the wheate and the barley, as freshe as yf menne hadde but nowe 
thrashed it,” 
