20 THE DEPTHS OF THE SEA 



fessor Wyville Thomson and Dr. W. B. Carpenter for 

 a six weeks' dredging trip in the North Atlantic ; and 

 in the following year the Porcupine, by permission of 

 the Admiralty, made three trips under the guidance of 

 Dr. W. B. Carpenter and Mr. Gwyn Jeffreys. 



Towards the end of 1872 H.M.S. Challenger left 

 England to spend the following three years and a half 

 in traversing all the waters of the globe. This was 

 the most completely equipped expedition which has 

 left any land for the investigation of the sea, and its 

 results were correspondingly rich. They have been 

 worked out by naturalists of all nations, and form the 

 most complete record of the fauna and flora, and of the 

 physical and chemical conditions of the deep, which 

 has yet been published. It is from Sir John Murray's 

 summary of the results of the voyage that many 

 of these facts are taken. Since the return of the 

 Challenger there have been many expeditions from 

 various lands, but none so complete in its conception 

 or its execution as the British Expedition of 1872-1875. 

 The U.S.S. Blake, under the direction of A. Agassiz, 

 has explored the Caribbean Sea ; and the Albatross, of 

 the same navy, has sounded the Western Atlantic. 

 Numerous observations made by the German ships 

 Gazelle and Drache, and Plankton Expedition, the 

 Norwegian North Atlantic Expedition, the Italian 

 ship Washington, the French ships Travailleur and 

 Talisman, the Prince of Monaco's yachts, Hirondelle 

 and Princesse Alice, under his own direction, the 

 Austrian ' Pola ' Expedition, the Russian investiga- 

 tions in the Black Sea, and lastly, by the ships of our 

 own navy, have, during the last five-and-twenty years, 

 enormously increased our knowledge of the seas and 

 of all that in them is. This knowledge is still being 

 added to. At the present time the collections of the 

 German ship Valdivia and of the Dutch Siboga Expe- 

 dition are being worked out, and are impatiently 



