OF SELBORNE. 
205 
in OEloher 1775, on a mifty day, a particular oak in leaf dropped 
fo faft that the cart-way flood in puddles and the ruts ran with 
water, though the ground in general was dully. 
In Ibme of our fmaller iflands in the IVeft-Indies, if I miftake 
not, there are no fprings oi rivers ; but the people are fupplied 
with that neceffary element, water, merely by the dripping of 
fome large tall trees, which, ftanding in the bofoni of a mountain, 
keep their heads conftantly enveloped with fogs and clouds, from 
which they difpenfe their kindly never-cealing moifture; and 
fo render thofe diftridts habitable by condenfation alone. 
Trees in leaf have fuch a vaft proportion more of furface than 
thofe that are naked, that, in theory, their condcnfations Ihould 
greatly exceeed thofe that are ftripped of their leaves ; but, as the 
former imbibe alfo a great quantity of moifture, it is difficult to fay 
which drip moft : but this I know, that deciduous trees that are 
entwined with much ivy feem to diftil the greateft quantity. Ivy- 
leaves are fmooth, and thick, and cold, and therefore condenfe 
very fail; and befides ever-greens imbibe very little. Thefe fads 
may furnifb the intelligent with hints concerning what forts of trees 
they iliould plant round fmall ponds that they would wifh to be 
perennial ; and fhew them how advantageous fome trees are in pre- 
ference to others. 
Trees perfpire profufely, condenfe largely, and check evapor- 
ation fo much, that woods are always moifl ; no wonder therefore 
that they contribute much to pools and ftreams. 
That trees are great promoters of lakes and rivers appears 
from a well known faft in North-America-, for, fince the woods and 
forefts have been grubbed and cleared, all bodies of water are much 
diminiflTied ; fo that fome ftreams^ that were very confiderable a 
cent'.iyy 
