xxxn IP VOYAGE OF H.M.S. CHALLENGER. 



dried up. 1 Aristotle's opinions regarding ocean physics must be viewed as mere specula- 

 tions, but his researches on marine animals were of distinct scientific value. He named 

 and described more or less minutely one hundred and sixteen species of fishes, about 

 twenty-four species of Crustaceans and Annelids, and some forty Molluscs and Radiates, 1 

 making a total of one hundred and eighty species inhabiting the iEgean Sea ; and the 

 student is still reminded of his study of the anatomy of Ecldnus by the significant 

 name " Aristotle's Lantern " applied to its masticatory apparatus. 



After Aristotle no original inquirer into these matters appeared for many centuries. 



Pliny the elder (23-79 a.d.), in his gossipy "Natural History," presents Aristotle's 

 discoveries modified by much subsequent superstition and tradition. He concisely 

 catalogues marine animals into one hundred and seventy-six species, being four less than 

 the number recorded by Aristotle in the iEgean Sea alone. Pleased with this enumera- 

 tion, he then exclaims : — " Surely then everyone must allow that it is quite impossible 

 to comprise every species of terrestrial animal in one general view for the information 

 of mankind. And yet, by Hercules ! in the sea and in the Ocean, vast as it is, there 

 exists nothing that is unknown to us, and, a truly marvellous fact, it is with those 

 things which Nature has concealed in the deep that we are the best acquainted ! " 



Pliny had to confess himself unable to give a detailed account of the depth of the 

 ocean, some parts he stated to be 15 stadia (over 1500 fathoms) deep, others "immensely 

 deep, no bottom having been found ; " 3 but he makes up for this in a way by explaining 

 very clearly " why the sea is salt." He says : — " Hence it is that the widely diffused 

 sea is impregnated with the flavour of salt, in consequence of what is sweet and 

 mild being evaporated from it, which the force of fire easily accomplishes ; while all 

 the more acrid and thick matter is left behind, on which account the water of the 

 sea is less salt at some depth than at the surface." 4 



In this explanation Pliny followed Aristotle, and helped to open up a magnificent 

 arena for the hair-splitting scholastics of the Middle Ages to dispute in. Bishop 

 Watson* says: — "There are few questions respecting the natural history of the globe 

 which have been discussed with more attention, or decided with less satisfaction, than 

 that concerning the primary cause of the saltness of the sea. The solution of it had 

 perplexed the philosophers before the time of Aristotle ; it surpassed his own great 

 genius, and those of his followers who have attempted to support his ■ arguments have 

 been betrayed into very ill grounded conclusions concerning it. Father Kircher, 6 after 

 having consulted three and thirty authors upon the subject, could not help remarking, 

 that the fluctuations of the ocean itself were scarcely more various than the opinions of 



1 Meteoiolog., lib. ii. cap. iii. 



2 De Animal. Hist., lib. iv. cap. i.-vii. ; Eng. Iransl. by O^lc, pp. 97-115, London, 1882. 



3 Hist. Nat., lib. ii. cap. cii. 4 Ibid., lib. ii. cap. c. 



6 Chemical Essays, vol. ii. pp. 93, 94, 2nd cd., 1782. ■ Mundus Subtemmeus, Liber iii. chap. iii. 



