SUPPLEMENT. 
On page 58, mention was omitted of the fact, that the period of the pen- 
dulum may be somewhat altered by an imparted oscillation of the support. 
As this was of course not forgotten in treating of the observations, the fol- 
lowing considerations may be inserted here. 
We will first 'consider the observations that were made out on the ice 
between the 8th and the 11th June, 1895. As mentioned on page 32, the iron 
cross on which the pendulum apparatus was placed, was in immediate contact 
with the ice. This was effected by scraping away the snow from the floor 
of the snow hut in which the observations were made, until homogeneous, solid 
ice was reached, when the iron cross was laid upon it. The cross became 
firmly attached to the ice, and was so steady that the position of the level 
of the pendulum apparatus remained almost unchanged from day to day 
during the time that the observations were being made. Lieut. Scott-Hansen 
also {notes it as his impression that this setting up of the instrument was 
the steadiest during the whole expedition. As the pendulum apparatus stood 
immediately upon the floor of the hut, Scott-Hansen had here, too, to carry 
out his observations in a recumbent position. The ice at that time being 
depressed by the surrounding snow-drifts, water continually penetrated into 
the hut, and kept the floor wet, so that it was necessary now and then to 
remove the water by throwing dry snow into it, and then shovelling away the 
slush. It afterwards appeared that the floor of the snow-hut was rather below 
the level of the sea; for immediately after the observations were terminated, 
the ice cracked right across it, and the water rose to such a height, that if 
the apparatus had been in position, the bob of the pendulum would have 
been a few centimetres below the surface of the water. 
