president's addeess. 183 



the deepest interest, we find that Aristotle had already made re- 

 searches (b.c. 384-322) on marine animals that were of distinct 

 scientific valne. He named and described more or less minutely, in 

 his " Natural History of Animals," 116 species of fishes, about 24 

 species of Crustaceans and Annelides, and some 40 Molluscs and 

 Radiates, making a total of 180 species inhabiting the ^gean Sea. 



Following this great philosopher, but nearly four hundred years 

 later, Pliny the elder (a.d. 23-79), in his "Natural History," presents 

 Aristotle's discoveries modified by much subsequent superstition 

 and tradition. He concisely catalogues marine animals into 176 

 species, being four less than the number recorded by Aristotle in 

 the ^gean Sea alone. Pleased with this enumeration, he then 

 exclaims: "Surely, then, everyone must allow that it is quite im- 

 possible 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 ive are the best 

 acquainted .' " ^ 



How strangely this confidence of Pliny in the knowledge of his 

 time contrasts with Professor Moseley's remark, made almost 1900 

 years later, that, " by our deep-sea explorations, we obtain, for the 

 first time, a glimpse of the fauna and flora of nearly three-fourths of 

 the earth's surface," and " our whole knowledge of the sea-bottom has 

 been created ivithin a few years,'''' whilst "before that time we knew 

 little of its fauna and flora beyond what is found on a comparatively 

 narrow belt of the coast-line." 



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

 depth of the ocean, some parts of which he stated to be 15 stadia (over 

 .1500 fathoms) deep, others "immensely deep, no bottom having been 

 found " ; 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 

 diilused sea is impregnated with the flavour of salt, in consequence of 

 what is sweet and mild being evaporated from it, which the force of 

 the fire [of the sun ?] easily accomplishes ; while all the more acrid 

 [saline ?] and thick matter is left behind, on which account the water 

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



This inquiry as to the saltness of the sea remained a subject of 

 controversy through the Middle Ages and gave rise to a vast amount 

 of unprofitable literature. Kirch er, after consulting three aiul thirty 

 authors upon the subject, could not help remarking that " tlie 

 fluctuations of the ocean itself were not more various than the 

 opinions of men concerning the origin of the salt in the sea." In 

 1865 a paper by Professor Porchhammer of Copenhagen, on the 

 Composition of Sea-water in different parts of the Ocean, was published 

 in the "Philosophical Transactions" recording the result of twenty 

 years of patient work, and its publication made an era in the history of 



Sir Wyville Thomson' (3 Narrative of the " Challenger." 



