INTRODUCTION 
3 
circulation of the water in a salt- and a fresh-water lake, under the 
influence of wind and other physical agents. 
In a salt-water loch, again, there is a great profusion of life in 
depths of 500 and 600 feet, and many organisms from these depths, as 
well as large numbers of other organisms taken at the surface, exhibit 
most remarkable displays of phosphorescent light. In a fresh-water 
loch, from similar depths, and under the same climatic conditions, the 
dredge or trawl brings up not more than half a dozen dwarfed species, 
and the phenomenon of phosphorescent light has never been observed in 
fresh- water organisms.^ The organic matter associated with the muds 
and other deposits from a salt-water loch undergoes rapid decomposi- 
tion, and soon renders the water foul and unsuited for living creatures. 
In the deposits from a fresh-water loch, although chemical analysis 
shows abundance of organic matter, the water does not become foul so 
rapidly, and organisms may live in water associated with the deposits 
for days and weeks. These phenomena are apparently connected with 
the activity of two species of bacteria in decomposing the sulphates in 
solution — Microspira desulphiuicans in fresh water, and Microspira 
estuarii in salt water. 
The above and many similar observations led me to conclude that 
a systematic survey of the fresh -water lochs of Scotland would in all 
likelihood result in many new additions to natural knowledge, and 
would be especially important for comparison with results in other 
departments of scientific endeavour. I found that many geologists 
were most anxious for a bathymetrical survey of these lochs, in con- 
nection with the discussion as to the origin of lake-basins. Fisher- 
men, and engineers who had to do with the water supply of towns 
and the development of water power, were also interested in this subject. 
On my initiation this matter was brought before the Councils of the 
Royal Society of London and of the Royal Society of Edinburgh. 
After careful consideration both Councils during the years 1883 and 
1884 made very strong representations to the Government, urging 
that a bathymetrical survey of the Scottish fresh -water lochs should 
be at once undertaken in the interests of scientific progress. There 
was no practical outcome from these representations. The reply of the 
Treasury, dated 17th September 1883, and signed by Mr Leonard 
Courtney (now Lord Courtney), was to the effect that a survey of the 
kind indicated did not come within the functions of the Admiralty, 
which only undertook work in the interests of navigation, nor of the 
Survey Department of the Office of Works (late Ordnance Survey), 
which limited its operations to the dry land, and that, however 
interesting from a scientific point of view, their Lordships were unable 
1 See notes by T. Jamieson in the Aberdeen Free Press, 19th November 1908, 
and in Nature, vol. Ixxix. p. 309, 1909, as to phosphorescent displays in Loch Builg. 
