2 
THE FKESH-WATER LOCHS OF SCOTLAiS^D 
Mr H. N. Dickson, the late Mr John Rattray, and many other 
physicists, chemists, and biologists took part.^ 
While carrying on these researches in the sea-lochs of Scotland 
the Medusa made several excursions into the fresh -water lochs in the 
line of the Caledonian Canal — Loch Lochy, Loch Oich, and Loch Ness. 
Nothing could be more striking than the difference in the physical and 
biological conditions presented by the salt- and the fresh-water lochs. 
In salt water the maximum density point is below the freezing point, 
so that the colder water at the surface always tends to sink to the 
bottom. In fresh water the maximum density point is 39° '2 Fahr., 
so that water at this temperature tends to sink to the bottom, while 
water above or below 39° '2 Fahr. remains at the surface. This physi- 
cal fact governs the very different distribution of temperature and 
' Cuniiingliam, J. T., " On the Relations of the Yolk to the Gastriila in 
Teleosteans, and in other Vertebrate Types," Quart. Journ. Micr. Sci., vol. xxvi., 
N.S., p. 1, 1885. 
Henderson, J. R., " The Decapod and Schizopod Crustacea of the Firth of 
Clyde," Trans. Nat. Hist. Soc. Glasgoiv, 1886. 
Murray, John, "The Physical and Biological Conditions of the Seas and 
Estuaries about North Britain : Paper read before the Philosophical Society 
of Glasgow, 31st March 1886, and published in Proc. Phil. Soc. Glasgow, vol. xvii. 
pp. 306-333, 1886. 
Murray, John, " On the Effects of Winds on the Distribution of Temperature 
in the Sea- and Fresh- Water Lochs of the West of Scotland," Scot. Geogr. Mag., 
vol. iv. pp. 345-365, 1888. 
Giinther, A., "Report on the Fishes obtained by Mr J. Murray in Deep Water 
on the North-West Coast of Scotland, between April 1887 and March 1888," 
Proc. Roy. Soc. Edin., vol. xv. pp. 205-220, 1888. 
Cunningham, J. T., and R. Vallentin, " The Luminous Organs of Nyctiphanes 
norvegica,^^ Proc. Roy. Soc. Edin., vol. xiv. pp. 351-356, 1887 ; also Quart. Journ. 
Micr. Sci, vol. xxviii. pp. 319-343, 1888. 
Rattray, John, " Revision of the Genus Aulacodiscus ; Revision of the Genus 
Auiisca,'' Journ. Roy. Micr. Soc, 1888. 
Hoyle, W. E., "On the Deep-Water Fauna of the Clyde Sea- Area (with map)," 
Journ. Linn. Soc. Lond., Zoology, vol. xx. pp. 442-472, 1889. 
Murray, John, " On the Temperature of the Salt- and Fresh- Water Lochs of the 
West of Scotland, at different Depths and Seasons, during the years 1887 and 
1888," Proc. Roy. Soc. Edin., voL xviii. pp. 139-228, 1891. 
Murray, John, and R. Irvine, " On Silica and the Siliceous Remains of 
Organisms in Modern Seas," Proc. Roy. Soc. Edin., vol. xviii. pp. 229-250, 1891. 
Mill, H. R., " The Clyde Sea Area," Trans. Roy. Soc. Edin., vol. xxxvi. pp. 641 
and 664, 1892. 
Murray, John, and R. Irvine, " On the Chemical Changes which take place in 
the Composition of the Sea- Water associated with Blue Muds on the Floor of the 
Ocean," Trans. Roy. Soc. Edin., vol. xxxvii. p]3. 481-507, 1893. 
Murray, John, and R. Irvine, "On the Manganese Oxides and Manganese 
Nodules in Marine Deposits," Trans. Roy. Soc. Edin., vol. xxxvii. pp. 721-742, 
1894. 
And numerous other papers. 
