It is known that seven considerable streams fall into this basin, and hence it was long supposed that it must discharge its superfluous stores by subterranean channels into the Mediteranean or the Red Sea. This opinion is now everywhere relinquished, in consequence of the learned remarks on the effect of evaporation in a hot climate, published by Dr. Halley many years ago; the justness of which were admitted by Dr. Shaw, though he calculated that the Jordan alone threw into the lake every day more than six million tuns of water. It is deserving of notice, that the Arabian philosophers, if we may believe Mariti, had anticipated Halley in his conclusions in regard to the absorbent power of a dry atmosphere.[113] The marvellous properties usually assigned to the Dead Sea by the earlier travellers have vanished upon a more rigid investigation. It is now known that bodies sink or float upon it, in proportion to their specific gravity; and that, although the water is so dense as to be favourable to swimmers, no security is found against the common accident of drowning. Josephus indeed asserts that Vespasian, in order to ascertain the fact now mentioned, commanded a number of his slaves to be bound hand and foot and thrown into the deepest part of the lake; and that, so far from any of them sinking, they all maintained their place on the surface until it pleased the emperor to have them taken out. But this anecdote, although perfectly consistent with truth, does not justify all the inferences which have been drawn from it. "Being willing to make an experiment," says Maundrell, "I went into it, and found that it bore up my body in swimming with an uncommon force; but as for that relation of some authors, that men wading into it were buoyed up to the top as soon as they got as deep as the middle, I found it, upon trial, not true."[114] The water of this sea has been frequently analyzed both in France and England. The specific gravity of it, according to Malte Brun, is 1.211, that of fresh water being 1.000. It is perfectly transparent. The applications of tests, or reagents, prove that it contains the muriatic and sulphuric acids. There is no alumina in it, nor does it appear that it is saturated with marine salt or muriate of soda. It holds in solution the following substances, and in the proportions here stated: Muriate of lime 3.920 Magnesia 10.246 Soda 10.360 Sulphate of lime .054