58 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 
\ 
was registered on the photographic plates, even after two — 
hours’ exposure. The observations show that light in con- 
siderable quantity penetrates to a depth of at least 1,000 metres, 
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 
fms., are found fishes of a silvery and greyish hue, along with 
red-coloured Crustaceans. At depths of from 500 fms. down- 
wards black fishes make their appearance, 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 1913 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 1s 
probably the best introduction to Oceanography that can be 
recommended to the junior student or the intelligent non- 
specialist enquirer 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 
