392 Beck on Salt Storms, ^c. 



by the saline quality of the air ? The native plants are 

 doubtless accustomed to its action, and do not so sensibly feel 

 its injurious effects. And if the Egyptian air is so very pene- 

 trating from this very cause, as to produce ophthalmia, may 

 we Bot rationally conclude, that its influence must be equally 

 injurious to plants not accustomed to it. 



Another illustration of the influence of salt on vegetation is 

 to be found in the Dead Sea, or Lake Asphaltites. "■ In Lake 

 Asphaltites," says Volney, " there is neither animal nor 

 vegetable life. No verdure is to be seen on its banks, nor 

 fish to be found within its waters ; but it is not true, that its 

 exhalations are pestiferous, so as to destroy birds flying over 

 it. It is not uncommon to see swallows skimming its surface, 

 and dipping for the water necessary to build their nests. The 

 true cause which deprives it of vegetables and animals is the 

 extreme saltness of the water, which is vastly stronger than 

 that of the sea. The soil around it, equally impregnated with 

 this salt, produces no plants, and the air itself, which becomes 

 loaded with it from evaporation, and which receives also the 

 sulphureous and bituminous vapours, cannot be favourable to 

 vegetation ; hence the deadly aspect which reigns around this 

 lake."* 



3. In what way does the salt operate in producing its 

 deleterious effects on the leaves of vegetables ? It is by no 

 means easy to answer this question. It cannot be by shutting 

 up the pores of the leaf, and thus obstructing its perspiration. 

 It is well known that when the surfaces of leaves are covered 

 with oil, they will soon die.j But salt water is certainly not 

 sufficiently viscid to act in a similar way. 



Nor can it be satisfactorily attributed to the difference 

 of structure between maritime and land plants. There is 

 some difference indeed between many of these, maritime 

 plants being generally covered by a pubescence, of which 

 most land plants are destitute. It is idle however to suppose 

 that the object of this covering is to protect maritime plants 

 from the action of the salt air, as there are many of them 



* Volnej-'s Travels in Syria and Egj'pt. Vol. I. p. 217. 

 f Darwin's Botanic Garden. P. 256. 



