96 FOUNDERS OF OCEANOGRAPHY 



least 1,000 metres (547 fathoms), which is much deeper than 

 had been previously supposed. It was shown that the red 

 rays of light are those that disappear first, and the ultra 

 violet are those that penetrate most deeply. 



(4) A special study was made on the " Michael Sars " 

 of the characteristic colour of the fishes in various zones of 

 depth. In the superficial layers of the ocean small colourless 

 or transparent forms abound, forming a part of the well- 

 known pelagic fauna. Below this, at an average depth of 

 about 200 fathoms, are found fishes of a silvery and greyish 

 hue, along with red-coloured Crustaceans. At depths of 

 from 500 fathoms downwards black fishes make their appear- 

 ance, still associated with red Crustaceans and other strongly 

 coloured red, brown, or black Invertebrates. This chapter 

 is illustrated by some beautiful coloured plates of the fishes. 



(5) Lastly, the " Michael Sars " got important evidence 

 in support of the view that the fresh-water eel spawns south 

 of the Azores, and that the larvae are carried by currents 

 back to the coasts of North-west Europe. 



In 1 9 1 3 Murray published in the Home University Library a 

 small book of about 250 pages, entitled The Ocean : A General 

 Account of the Science of the Sea, which is undoubtedly the 

 most concise and accurate and, so far as is possible within its 

 small compass, complete account that has yet appeared of 

 all that pertains to the scientific investigation of the sea. 

 It is written in simple language for the general reader, and is 

 probably the best introduction to oceanography that can be 

 recommended to the junior student or the intelligent non- 

 specialist inquirer who desires information merely as a matter 

 of general culture. It deals with the history, methods, and 

 instruments of marine research, the depths and physical 

 characters of the ocean, the circulation of the waters, life in 

 the ocean, submarine deposits, and finally the nature and 

 relations of the various " Geospheres " that constitute the 

 globe. Coloured maps and plates illustrate depths, salinities, 

 temperatures, currents, deposits, and many of the charac- 



