INTRODUCTION. 



Knowledge possessed by the Ancients concerning the Ocean, its Saltness and its Inhabitants— Researches during the 

 Middle Ages, the Fifteenth, Sixteenth, and Seventeenth Centuries — The Expeditions of the Eighteenth Century, 

 and the Arctic and Antarctic Expeditions of the early part of the Nineteenth Century — The "Lightning" and 

 " Porcupine" Expeditions — Correspondence between the Royal Society and the Admiralty with reference to the 

 investigation of the Great Ocean Basins. 



A brief review of the efforts made to acquire a knowledge of the Ocean, and a general 

 account of the opinions held prior to the year 1872 as to the physical and biological 

 conditions of the great ocean basins, may form an appropriate Introduction to the 

 Narrative of the Voyage of H.M.S. Challenger. The objects which the promoters had in 

 view when they urged Her Majesty's Government to fit out and despatch an Expedition 

 on a special scientific investigation of the depths of the sea will thus be indicated. 



The sea and the life in its waters were little studied by the learned men of the 

 ancient civilisations, which were clustered round the nearly tideless Mediterranean. 

 Their sea-lore consisted in great part of wildly exaggerated descriptions of the more 

 striking marine phenomena woven into a vague mythology. The sea was an object of 

 terror, for navigation was uncertain in the extreme ; what lay beyond the Pillars of 

 Hercules was veiled in mystery, and what lay beneath the surface of the waters crossed 

 by the ancient navies was equally unknown. 



The sea was not, so far as is known, made the subject of close attention until 

 Aristotle (384-322 B.C.) brought his mind to bear on it in common with the other 

 departments of natural history. Aristotle studied the physical conditions of the sea 

 as far as a man without apparatus could study them. He thought that in the ocean 

 the water was warmer and Salter at the surface than at the bottom; he considered that 

 as the sun's heat was always evaporating the water the sea would ultimately be 



(naki!. (jiiai.j.. BXP. — vol.. i. — 1685.) / 



