LETTER XXIX 



TO THE SAME 



SELBORNE, Feb. 7, 1776. 



DEAR SIR, In heavy fogs, on elevated situations espe- 

 cially, trees are perfect alembics ; and no one that has not 

 attended to such matters can imagine how much water one 

 tree will distil in a night's time, by condensing the vapour, 

 which trickles down the twigs and boughs, so as to make the 

 ground below quite in a float. In Newton-lane, in October 

 1775, on a misty day, a particular oak in leaf dropped so 

 fast that the cart-way stood in puddles and the ruts ran 

 with water, though the ground in general was dusty. 



In some of our smaller islands in the West-Indies, if I 

 mistake not, there are no springs or rivers ; but the people 

 are supplied with that necessary element, water, merely 

 by the dripping of some large, tall trees, which, standing 

 in the bosom of a mountain, keep their heads constantly 

 enveloped with fogs and clouds, from which they dispense 

 their kindly never-ceasing moisture ; and so render those 

 districts habitable by condensation alone. 



Trees in leaf have such a vast proportion more of sur- 

 face than those that are naked, that, in theory, their con- 

 densations should greatly exceed those that are stripped of 



