DRIPPING OF TREES. 195 



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, f 



* The house in which we resided in Fife was built on a greenstone rock, 

 on the south brow of the high ground overlooking the beautiful river 

 Leven, about two hundred feet above its level, and five hundred feet 

 distant from it. We there remarked, that, even in closets in the garrets, 

 shoes, and all kinds of leather, soon became mouldy, which could be 

 produced only by the moisture generated by the trees, which in thick 

 groves closely surrounded the house. ED. 



f* There are no rivulets, or springs, in the island of Ferro, the westmost 

 of the Canaries, except on apart of the beach, which is nearly inaccessible. 

 To supply the place of a fountain, however, Nature, ever bountiful, 

 has bestowed upon this island a species of tree, unknown to all other parts 

 of the world. It is of moderate size, and its leaves are straight, long, and 

 evergreen. Around its summit a small cloud perpetually rests, which so 

 drenches the leaves with moisture, that they continually distil upon the 

 ground a stream of fine clear water. To these trees, as to perennial 

 springs, the inhabitants of Ferro resort ; and are thus supplied with an 

 abundance of water for themselves and for their cattle. 



The trunk of this tree is about nine feet in circumference ; the top 

 branches are not higher than thirty feet from the ground ; the circum- 

 ference of all the branches together is one hundred and twenty feet ; the 

 branches are thick, and extended, the leaves being about three feet nine 

 inches from the ground. Its fruit is shaped like that of the oak, but 

 tastes like the kernel of a pine apple, and the leaves resemble those of the 

 laurel, but are longer, wider, and curved. 



Trees require a great quantity of water to supply their organs. This 

 is given off in perspiration by their leaves. In the experiments of Hales 

 on the quantity of water taken up by plants, it was found that a pear- 

 tree, which weighed seventy-one pounds, absorbed fifteen pounds of water 

 in six hours ; and that branches of an inch diameter, and from five to 

 six feet high, sucked up from fifteen to thirty ounces in twelve hours. 

 When these were stript of their leaves, they only sucked up one ounce in 

 twelve hours. 



The white birch tree, betula alba, is noted on account of the wine that 

 is extracted from it, and is said to possess the medical qualities of an anti- 

 scorbutic, deobstruent, and diuretic. The method of bleeding the tree 

 is performed thus: About the beginning of March, an oblique cut is 



