EFFECTS OF FOEEST VEGETATION ON CLIMATE. 195 



a mountain is the destruction of a number of lightning con- 

 ductors equal to the number of trees felled ; it is the modifica- 

 tion of the electrical state of an entire country ; the accumulation 

 of one of these elements indispensable to the formation of hail, 

 in a locality where previously this element was dissipated by the 

 silent and incessant action of the trees. On this point (he says) 

 observations support theoretical deductions. According to a 

 detailed statistical account, the losses occasioned by hail in the 

 continental states of the King of Sardinia, from 1820 to 1828 

 inclusively, amount to the sum of forty-six millions of francs 

 (£1,916,666 sterling). Three provinces, those of A"al d'Aoste, 

 the Yallee de Suze, and Haute Maurienne, do not appear in these 

 tables ; they were not visited by hail storms. The mountains of 

 tliesG three provinces are the hest wooded. The warmest province, 

 that of Genoa, the mountains of which are well covered, is scarcely 

 ever visited by this meteor." * * * * " It is said to ho.ve 

 been remarked in Italy, that in proportion as rice-fields multiply, 

 the annual quantity of rain has gradually increased, and that 

 the number of rainy days has augmented in proportion." A gain, — 

 " the wind exercises a direct action on vegetables, often very 

 injurious, and which ought to be carefully distinguished from 

 climatological action. It is against this direct action that 

 curtains of wood, by forming a shelter, are especially useful. 

 The direct influence of the wind on the phenomena of vegetation 

 is nowhere more strikingly exemplified than in the Isle of 

 France. The south-east wind, very healthy both for man and 

 animals, is on the contrary, a perfect scourge to the trees. 

 Fruit is never found on the branches directly exposed to this 

 wind ; none is to be found but on the opposite side. Other 

 trees are modified even in their foliage ; they have only half a 

 head, the other has disappeared under the action of the wind. 

 Orange and citron trees become superb in the woods ; in the 

 plain and where they are without shelter they always continue 

 weak and crooked." — Annuaire jpour Van 1846. 



Professor Laurent, of Nancy, instances Fonteu ay and Provence 

 as places where the felling of forests has affected the climate. 

 Wells and pits have become dry on this account. In the whole 

 of the Eastern Pyrenees and the Herault, the felling of timber 

 has been attended by serious consequences. The temperature 

 becomes higher, wells and watercourses diminished, and the dry- 

 ness of the climate was much increased. He also quotes similar 

 results in the Yosges, Department of Garde, Nismes, Bezieres, 

 Isere, &c.- — Be V influence de la Culture sur V Atmosphere, S{c. 



Professor Chaix, of Geneva, attributes the well-known floods 

 and inundations of the Ehone, such as those of 1803, 1810, 1811, 

 1840, 1841, 1842, i]i part to the destruction of the great extent 



