3L0 
Proceedings of the Royal Society of Edinburgh. [Sess. 
individuals of that wonderfully archaic siphonopod Spivula, and of 
numerous leptocephalus larvm of the common European eel in mid- 
Atlantic, south of the Azores — an important addition to the data available 
towards a solution of the problem of the life history of that elusive fish. 
Much of the most interesting and important work of the expedition 
bore upon the relations of organisms to physical environmental conditions. 
Thus, in relation to depth, the Michael Sars results point to the great 
poverty of life at the extreme depths and to its comparative richness at 
intermediate depths — in contradiction to commonly held views. Particularly 
important studies were made bearing on the relationships of pelagic 
animals to light. The Michael Sars naturalists did not fall into the 
common blunder of supposing that a deep-sea animal which looks red when 
drawn up to the surface does so in its native haunts, but fully realised that 
such animals at the depths in which they live, where no red rays penetrate, 
have simply a dark appearance like those of their fellows which actually 
are dark-coloured when seen by ordinary daylight. The upper limit of 
these dark-coloured and red organisms of deep water was found to vary in 
level at different latitudes in a manner corresponding to the different 
depths to which daylight penetrates, being deeper in low latitudes and at a 
less depth in higher latitudes. Careful measurements were made of the 
actual depths to which daylight penetrates by exposing sensitive photo- 
graphic plates submerged at different depths. 
Apart from the splendid additions to detailed knowledge which the 
Michael Sars Expedition has produced, a lesson of great general importance 
for the future of oceanography has been taught, viz. that oceanographical 
research of the highest class may be carried out even in the deepest and 
most extensive oceans by means of a vessel no larger than an ordinary 
o^ood steam trawler.^^ 
While Murray’s achievements in pure science — the Challenger Expedition, 
the Scottish Lake Survey, and the Michael Sars Expedition, and the 
researches centred round them — are what concern us more especially, these 
by no means exhausted his activities. 
Of Murray’s achievements outside the realm of pure science there is none 
of greater interest than that extraordinary by-product of his Challenger 
work by which he converted an almost unknown and uninhabited tropical 
island into a busy hive of industry and a valuable centre of commercial 
activity. The initial discovery was made during the routine examination of 
oceanic deposits, for amongst a certain series of samples Murray detected a 
* The Michael Sars measures 125 feet between perpendiculars, is of 226 tons burden, 
and has engines of 300 horse-power which give her a speed of 10 knots. 
