TEREESTEIAL PHENOMENA. 47 



generated from burnt earth, but that this was absurd, 

 although it was true that the saltness of the sea was pro- 

 duced from something of this kind. His own explanation, 

 which is difficult to follow, seems to be that dry and earthy 

 exhalations were mixed in some way with rains and im- 

 parted a saltness to them.* Southerly winds and the first 

 autumnal rains, he says, are especially salt, for the southerly 

 winds blow from dry and hot places and so contain little 

 moisture but a large quantity of the dry exhalation to which 

 the saltness is due.f Aristotle had evidently noticed that 

 winds blowing from Africa and across the sea to Greece 

 were salty near the coast. That this saltness was due to 

 the presence of particles of salt and fine sea spray he does 

 not seem to have known. He considered it rather as a 

 proof of the presence of the dry exhalation to which he 

 decided that the saltness was due. There is a fatal objection 

 to Aristotle's explanation, viz., that, if it were true, the 

 rivers also ought to be salty. Olympiodorus, who wrote a 

 commentary on the Meteorology, deals with this objection 

 in a fanciful way, and argues that, in order that a mingling 

 of the exhalation with water may take place, the water 

 ought to be at rest and not constantly flowing like that of 

 rivers, and, furthermore, that the exhalation always tends 

 towards the sea, which is lower than the rivers. X 



Aristotle's views, or modifications of them, were gener- 

 ally accepted until the middle of the seventeenth century. 

 Boyle says that the Aristotelians of his time derived the 

 saltness of the sea from the strong action of the sun's rays 

 on the water, and he also says : " But some of the cham- 

 pions of Aristotle's opinion are so bold as to allege experience 

 for it, vouching the testimony of Scaliger to prove that the 

 sea tastes salter at the top than at the bottom, where the 

 water is affirmed to be fresh. § The Aristotelians thus 

 misrepresented Aristotle, who distinctly asserts, in Meteorol. 

 ii. c. 2, that the salt water sinks because of its heaviness, 

 while fresh water is borne upwards. Theophrastus did not 

 accept Aristotle's explanation, for, according to Olympio- 

 dorus, || he believed that the saltness of the sea was due to 

 exhalations from the earthy bed of the sea. 



When dealing with the phenomena of relative changes 



* Meteorol. ii. c. 3, ss. 24 and 25. f Ibid. ii. c. 3, ss. 26 and 27. 

 X In Meteora Arist. Comment., edit. J. B. Camotius, Venice, 1567, p. 61. 

 § The Works of the Honourable Robert Boyle, new edition, London, 

 1772, vol. iii. p. 765. || Op. cit. p. 60. 



