The Editor,
The Journal of Glaciology
Sir, The Mechanical Measurement of Glacier Motion
In his article on this subject (Journal of Glaciology, Vol. 2, No. 19, 1956, p. 642) Mr. Galloway speaks of measurements of the movement of Lvngsdalsbreen with a new instrument which one can class in the general category of Gletsrheruhr; he also cites earlier experiments in this direction. These investigations should meet with great general interest since we know far too little about the actual course of glacier movement, particularly over very short periods of time. At the same time it seems that Mr. Galloway is not aware of the fact that I have also carried out measurements in Norwegian glaciers, particularly in Nigardsbrcen (Jostedalsbreen), with an instrument which I designed expressly for the purpose, and I would therefore like to draw attention to this work. (See references below.)
The Cryocinegraph which 1 developed was erected on a glacier tongue after laboratory tests, and was in operation there for several weeks, the results being to some extent surprising; 1 published these results in due course. (See below.) According to my experience of the results obtained with instruments of this type they must be regarded sceptically when insufficient attention is paid to ablation and when the forces exerted on the instrument are not taken into account.
It would be very desirable if Mr. Galloway would say a little more on this aspect of the problem since 1 find difficulty in understanding how this, after all, rather heavy instrument can move with the glacier ice without prejudicing the accuracy of the measurements.
The carrying out of measurements with this instrument above the glacier end seems to me essential, even though really favourable conditions for its setting up do not always exist. Generally there are only a few places where it can be erected and this applies too to the glacier end. Otherwise there is little prospect of success.
Schulenburger Landstrasse 3, Hannover-Hainholz, Germany 16 April 1956
