PAET I. 



INTRODUCTORY. 



CHAPTER I. 



THE EXPLORATION OF THE SEA. 



When, in December 1872, the Challenger left Portsmouth on 

 her memorable voyage methods of oceanographical discovery were 

 very imperfectly developed and what was then known of the 

 physics and biology of the deeper seas of the earth was neither 

 very exhaustive nor exact. There had indeed been many voyages- 

 of discovery in the course of which researches other than purely 

 geographical ones had been attempted, but it was only a few years 

 previous to 1872 that what we now recognise as oceanographical 

 investigation had been contemplated as an end in itself. Such 

 a colossal task as a systematic survey of the oceans of the globe 

 might usefully have been preceded by a preliminary study of the 

 apparatus and methods of the earlier cruises, and by some exten- 

 sive experiments applied to the perfection of these. This, however, 

 was not done and the ship left England on her three years' voyage 

 with an equipment containing little that was novel. But the 

 expedition was planned out spaciously, the ship was powerful and 

 commodious and her naval and civilian staff were efficient in the 

 highest degree. The apparatus was thus tested in every possible 

 way and an invaluable foundation was laid for later improvement. 



About a dozen oceanographical cruises of first rate importance 

 have been made since then and almost every detail of the 

 Challenge!' equipment has undergone refinement and improvement. 



J. F. 1 



