224 J. H. MAIDEN. 



of water will be held or retarded. The effect of transpir- 

 ation will be dealt with at page 228. 



The following statement may be literally true, although 

 the regularity of movement of the cloud referred to is 

 remarkable, and with the size of the tree and the quantity 

 of water rendered available we have nothing to do. 



"In an old work, mention is made of a celebrated tree in Ferro, 

 which is said to have furnished drinkable water to the inhabitants 

 of the island. According to the statement, every morning the 

 sea breeze drove a cloud towards the wonderful tree, which 

 attracted it to its huge top, and the water flowing from its foliage 

 uninterruptedly, drop by drop, was collected in cisterns." 1 



Mr. J. Burtt Davy in a recent work 2 speaks of the heavy 

 summer sea fogs, drifting high overhead across the narrow 

 stretch of bluff land, which are intercepted in their course 

 by the trees on the summits of the ridges, or, when they 

 lie low, roll along the broad river valleys and more numer- 

 ous narrow canyons opening into the redwood forests, 

 saturating the tree tops and by their means also the soil 

 below, with abundant moisture. 



I again quote Professor Hazen, 



"There is a class of visual observations which seem to show an 

 effect upon rainfall by the forest. Probably many have seen heavy 

 clouds pass over a plain, but which only precipitated as they 

 passed over a forest. Also in a hilly region it is a frequent 

 phenomenon that fog and low-lying clouds hover near a forest, 

 and not over an open plain. One also notes very often, in passing 

 into a forest on a damp day, that the trees drip moisture, possibly 

 condensed from the moisture evaporated from the damp earth 

 underneath. Observations of this nature, however, cannot 

 ordinarily be checked by instrumental means, but show in a 



1 J. Croumbie Brown, op. cit., p. 31. 



2 " Stock ranges of north-western California/' — Bulletin U.S. Depart- 

 ment of Agriculture, (page 12). 



