THE FRESH-WATER LOCHS OF SCOTLANH. 
423 
Embroideries on the curves were common, and were attributed to a 
long swell on the loch, to the wash of steamers, and frequently to the 
opening of lock-gates on the canal at Fort Augustus. 
With the view of gaining information on the effect of small variations 
in atmospheric pressure, a Dines’s sensitive barograph was obtained.* 
Records from an ordinary Richard barograph had indicated sudden 
barometric changes as a frequent cause of seiches, and the records of 
the sensitive barograph supported this view to a certain extent, although 
on some occasions the loch seemed unresponsive to changes in atmos- 
pheric pressure. On other occasions, however, the limnograph record 
seemed to be an accurate reproduction of the record obtained by means 
of the sensitive barograph. 
Loch Ness from its size proved to be rather unwieldy from the 
point of view of seiches, so that when, in the summer of 1905, the 
investigation of seiches was undertaken by Prof. Chrystal, he made 
his headquarters on Loch Earn, and gathered much information as 
to the cause of seiches from his observations.! 
Notes on the Deposits of Loch Ness. 
By G. W. Lee, d.Sc., and L. W. Collet, d.Sc., with Analyses of 
Selected Samples by A. Wilson, f.i.c. 
About sixty samples of the deposits covering the floor of Loch Ness 
were collected by the members of the Lake Survey staff from various 
parts of the loch, and were examined according to the methods used in 
the GJialle7iger Office for the study of marine deposits. 
They may be classed as follows : — 
(1) Bark grey mud, from the deep basin opposite Urquhart bay; 
(2) F errugineous mud, from the part of the Invermoriston deep basin 
opposite Horseshoe craig ; 
(3) Peaty mud, from the south-west end of the Invermoriston deep 
basin ; 
(4) Y ellow-grey clay, from off Inverfarigaig and off Cherry island; 
and 
(5) Brown sand, from shallow water off Urquhart bay. 
* The purchase of this instrument was facilitated by a grant from the Moray Bequest 
to the University of Edinburgh. 
f For further details the reader is referred to the following papers : — “ On the Hydro- 
dynamical Theory of Seiches, with a Bibliographical Sketch,” by Prof. Ohrystal, Trans. 
Roy. Soc. Ediii., vol 41 , p. 599 (1905); Calculation of the Periods and Nodes of Lochs 
Earn and Treig, from the Bathymetric Data of the Scottish Lake Survey,” by Prof. 
Chrystal and E. M. Wedderburn, Trans. Roy. Soc. Ediu., vol. 41 , p. 823 (1905); “An In- 
vestigation of the Seiches of Loch Earn by the Scottish Lake Survey,”; Part I. “ Limno- 
graphic Instruments and Methods of Observation,” by Prof. G. Ohrystal; Part II. “Pre- 
liminary Limuographic Observations on Loch Earn,” by James Murray, Trans. Roy. Soc. 
Edin., vol. 45 , p. 361 (1906). 
