148 EFFECTS OF DESTRUCTION OF FORESTS 



the observations of Marshal Marmont, and the evidence collected by 

 him in 1836. His conclusions have been disputed, if not confuted, 

 by Jomai-d and others, and are probably 'erroneous. See Foissac, 

 Meteorologie, German translation, pp. 634-639." 



The Imperial Academy of Science has expressed a wish that the 

 Government of Austria would apply to the Viceroy of Egypt for ex- 

 tracts from the observations which have been made on the rise of the 

 Nile gauge above Cairo for 3000 years and more, especially for ex- 

 tracts from the records of the last 200 years. Should these be 

 supplied, we may hope that some light may be incidentally cast upon 

 some of the questions at issue. 



South Africa has also its tale to tell. Mr Tuck, superintendent of 

 the Botanic Garden at Giahamstown, in writing to me before I left 

 the colony, communicated the following notice of what he had observed 

 in the course of the summer, that of 1864-1865 : — " This season has 

 been unusually hot and dry along the coast ; and all arouud Grahams- 

 town we have been unable to grow anything all this summer for 

 want of rain. The springs are all failing. 



" You may perhaps know the place of Mr J. J. Stone, on the top of 

 the hill on the Cowie road, towards the sea, marked out by a 

 quantity of Gum trees, on the ridge of the high hills to the south- 

 east of Grahamstown ; well, all through the summer we have had 

 only light misty rain, just enough to damp the grass, and not enough 

 to wet the ground, but these trees of Mr Stone's have there converted 

 the mist into rain. They have scarcely felt any effects of the dry 

 weather ; the vegetables and flowers have there grown all the summer 

 without watering ; there the tanks have always been full : and that 

 is the only place of which I have heard that it has been so within 

 five and twenty or thirty miles of Grahamstown." 



I have had occasion to cite the statements made by Boussingault 

 (ante p. 113) in regard to changes in the Lake of Tavarigua, in the 

 vicinity of New Valencia, in South America, otherwise they also might 

 have found a place here, as they show that a destruction of forests 

 had been followed by a lowering of the waters of the lake, and the 

 reproduction of the forests, consequent on the abandonment of culti- 

 vation, had been followed by a replenishing of the lake. 



By Dr Hough, who has given much attention to the subject in 

 America, it is stated, that " some twenty-five years ago the Danish 

 sland of Santa Cruz was a garden of freshness, beauty, and fertility. 



