SEICHES AND OTHER OSCILLATIONS 
33 
The space at mv disposal here will not permit me to enter into 
the history of recent seiche investigations outside of Scotland, 
although they have been many and important. For these I may 
refer the reader to the bibliography appended to H.T.S. ; to the 
excellent article by Professor Halbfass,^ the investigator of the 
Madlisee ; and to an admirable review published in Peterman7i's 
Geographische Mitteilungen, Heft ii. p. 16, 1908, by Dr Anton 
Endros, who is himself one of the most distinguished of modern 
seiche investigators. 
LiMNOGRAPHIC APPARATUS USED IN THE SuRVEY OF LoCHS EaRN, 
Tay, and Lubnaig 
One of the simplest and most effective of the instruments for 
measuring the denivellation of a lake is the index limnograph, 
originally devised by Endros. Fig. 9 shows the form used by the 
Scottish Lake Surveyors. The essential parts are the float, and its 
sheltering well and access tube ; a piece of fly-flshing line, passing 
from the float ov^er a small pulley to a counterpoise ; and an index, 
attached to the pulley, which indicates on a scale, that can be made 
as large as may be desired, the rotation of the pulley, which is of 
course directly proportional to the rise or fall of the float. The 
observer is provided with a piece of squared paper, the horizontal 
divisions of which represent half-minutes, and the vertical divisions 
the readings on the limnograph scale. An observation is made every 
half-minute, and a corresponding dot made on the recording paper. 
Through these dots is drawn with a free hand a curve which is called 
a " limnogram."' 
For many purposes it is desirable to have a continuous record, 
extending over a considerable time, for both night and day. For this 
purpose a special instrument was constructed after my design, which 
is called the "waggon recorder (fig. 10). It is really a combination 
of the essential principles of the older limnographs of Plantamour and 
Sarasin. The string of the index limnograph is replaced by a 
Chesterman's steel tape, which passes horizontally over two pulleys, 
between which it drags backwards and forwards a little waggon 
carefully mounted by means of three wheels, which run two on one 
and one on another of two parallel rails. The waggon carries an 
ordinary stylographic pen, so mounted as to write on a long strip of 
paper which is moved horizontally by rollers driven by clockwork. 
As the motion of the paper is perpendicular to the motion of the pen, 
caused by the rise and fall of the water, the result is the same as 
before, only the work and the patience are now transferred from the 
^ See footnote on p. 3L 
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