450 SALTNESS OF THE EED SEA. ' [Ch. XXII, 



must be regarded as a wide pan of enormous superficial extent, in 

 which the brine can easily reach the degree of concentration required." 



Another traveller, Major Harris, in his "'Highlands of Ethiopia," 

 describes a salt lake, called the Bahr Assal, near the Abyssinian fron- 

 tier, which once formed the prolongation of the Gulf of Tadjara, but 

 was afterwards cut off from the gulf by a broad bar of lava or of land 

 upraised by an earthquake. " Fed by no rivers, and exposed in a 

 burning climate to the unmitigated rays of the sun, it has shrunk into 

 an elliptical basin, seven miles in its transverse axis, half filled with 

 smooth water of the deepest casrulean hue, and half with a solid sheet 

 of glittering snow-white salt, the offspring of evaporation." " If," says 

 Mr. Hugh Miller, " we suppose, instead of a barrier of lava, that sand- 

 bars were raised by the surf on a flat arenaceous coast during a slow 

 and equable sinking of the surface, the waters of the outer gulf might 

 occasionally topple over the bar, and supply fresh brine when the first 

 stock had been exhausted by evaporation." * 



We may add that the permanent impregnation of the waters of a 

 large shallow basin with salt, beyond the proportion which is usual in 

 the ocean, would cause it to be uninhabitable by mohusks or fish, as 

 is the case in the Dead Sea, and the muriate of soda might remain in ex- 

 cess, even if it were occasionally replenished by irruptions of the sea. 

 Should the saline deposit be eventually submerged, it might, as we have 

 seen from the example of the Runn of Cutch, be covered by a fresh- 

 water formation containing fluviatile organic remains ; and in this way 

 the apparent anomaly of beds of sea-salt and clays devoid of marine 

 fossils, alternating with others of freshwater origin, may be explained. 



Dr. G. Buist, in a communication to the Bombay Geographical 

 Society (vol. ix.), has asked how it happens that the Red Sea should 

 not exceed the open ocean in saltness by more than -^th per cent. 

 The Red Sea receives no supply of water from any quarter save through 

 the Straits of Babelmandeb ; and there is not a single river or rivulet 

 flowing into it from a circuit of 4000 miles of shore. The countries 

 around are all excessively sterile and arid, and composed, for the most 

 part, of burning deserts. From the ascertained evaporation in the sea 

 itself, Dr. Buist computes that nearly 8 feet of pure water must be 

 carried off from the whole of its surface annually, this being probably 

 equivalent to T -i- ¥ th part of its whole volume. The Red Sea, therefore, 

 ought to have 1 per cent, added annually to its saline contents ; and 

 as these constitute 4 per cent, by weight, or 2-J per cent, in volume of 

 its entire mass, it ought, assuming the average depth to be 800 feet, 

 which is supposed to be far beyond the truth, to have been converted 

 into one solid salt formation in less than 3000 years.f Does the Red 

 Sea receive a supply of water from the ocean, through the narrow 

 Straits of Babelmandeb, sufficient to balance the loss by evaporation ? 



* Hugh Miller, First Impressions of England, 1847, pp. 183, 214. 

 f Buist. Trans, of Bombay Geograph. Soc, 1850, vol. ix. p. 38. 



