142 THE FRESH- WATER LOCHS OF SCOTLAND 
freezes all over, even in most vehement frosts, before February, but 
one night's frost thereafter will freeze it all over, and two nights then 
will make the ice of a very considerable thickness. This I did inquire 
after very sollicitously from the honestest and soberest of the adjoining 
Inhabitants and it was verified by so many that there was left no place 
to doubt the truth of the matter of fact. I have since heard of two 
other lakes, one of which is on lands belonging to myself called Loch 
Monar, of a pretty largeness, which steadily keeps the same method, 
and I have inquired after it by many who have affirmed it to me on 
their own knowledge. There is another little Lake in Straglash at 
Glencarrich on lands belonging to one Chissolm ; the Lake lies in a 
bottom 'twixt the tops of a very high hill, so that the bottom itself is 
very high. This Lake never wants Ice on it in the middle, even in the 
hottest summer, though it thaws near the edges. And this Ice is 
found on it, though the sun by reason of the reflexion from the hills 
in that country is very hot, and Lakes lying as high in the neighbour- 
hood have no such Phenomenon. 'Tis observable also, that about the 
borders of this Lake the Grass keeps a continual verdure, as if it were 
in a constant Spring and feeds and fattens beasts more in a week than 
any other grass doth in a fortnight. The matter of fact I have fully 
examined in both these, but to hit the cause requires a better philo- 
sopher than I am.'" 
Loch Monar is referred to above. The loch in Stratherrick is 
probably the small Loch Scriston, which was not sounded by the Survey. 
Apparently, however, it is very rarely frozen over. The reference to 
the lake which is never free from ice even in the hottest summer is of 
course apocryphal. 
Note. Since the foregoing article was written there have been 
published two papers which indicate that the temperature observations 
of the Lake Survey are of considerable importance as throwing light 
on temperature changes occurring in the ocean. The first of these 
papers is by Professor Otto Pettersson {Publications de Circonstance^ 
No. 47), describing oscillations in the deep water of the Skagerak with 
a period of fourteen days, which he thinks may be explained as a deep- 
water tide. The author has tried to show {Proc. Roy. Soc. Edin.^ 
vol. xxix. p. 602) that these oscillations may be explained in the same 
way as the temperature seiche in fresh water. The second paper is 
by Helland-Hansen and Nansen in the Report on Norwegian Fishery 
and Marine Investigations (vol. ii., 1909, p. 87), where "puzzling 
waves'" are discussed at some length. The authors say: "As far as 
we can see, it is one of (the) greatest problems (of Oceanography) 
that most urgently calls for a solution." It seems probable that 
the explanation of the temperature seiche also applies to them. 
