INFLUENCE OF THE FOREST ON PRECIPITATION. 185 
to the neighboring fields. * * The forest, presenting a con¬ 
siderable surface for evaporation, gives to its own soil and to 
all the adjacent ground an abundant and enlivening dew. 
There falls, it is true, less dew on a tall and thick wood than 
on the surrounding meadows, which, being more highly 
heated during the day by the influence of insolation, cool with 
greater rapidity by radiation. But it must be remarked, that 
this increased deposition of dew on the neighboring fields is 
partly due to the forests themselves; for the dense, saturated 
strata of air which hover over the woods descend in cool, calm 
evenings, like clouds, to the valley, and in the morning, beads 
of dew sparkle on the leaves of the grass and the flowers of the 
field. Forests, in a word, exert, in the interior of continents, 
an influence like that of the sea on the climate of islands and 
of coasts : both water the soil and thereby insure its fertility.” 
In a note upon this passage, quoting as authority the Historia 
de la Conquista de las siete islas de Gran Canaria , de Juan de 
Abreu Galindo , 1632, p. 47, he adds: “ Old historians relate 
that a celebrated laurel in Ferro formerly furnished drinkable 
water to the inhabitants of the island. The water flowed from 
its foliage, uninterruptedly, drop by drop, and was collected in 
cisterns. Every morning the sea breeze drove a cloud toward 
the wonderful tree, which attracted it to its huge top,” where 
it was condensed to a liquid form. 
In a number of the Missionary Herald , published at Bos¬ 
ton, the date of which I have mislaid, the Rev. Mr. Yan 
Lennep, well known as a competent observer, gives the fol¬ 
lowing remarkable account of a similar fact witnessed by him 
in an excursion to the east of Tocat in Asia Minor : 
“ In this region, some 3,000 feet above the sea, the trees 
are mostly oak, and attain a large size. I noticed an illustra¬ 
tion of the influence of trees in general in collecting moisture. 
Despite the fog, of a week’s duration, the ground was every¬ 
where perfectly dry. The dry oak leaves, however, had gath¬ 
ered the water, and the branches and trunks ot the trees were 
more or less wet. In many cases the water had run down the 
trunk and moistened the soil around the roots ot the tree. In 
