MOVEMENT OF THE BARRIER 411 
if the change in levels corresponded to the change in 
barometric gradient. 
In working up the meteorology notes, barometer 
figures based on Royds' journey — who went nearly parallel 
to the Barrier edge — were unfortunately used to obtain 
results for the Southern journey. 
Finally, we may conclude that the tendency of all the 
facts is to support the ^ Floating Barrier ' theory. 
V. Movement of the Barrier. — There is certainly not 
enough inclination in the Barrier ice sheet to account for 
its motion. The Bay of Whales (or Balloon Bight) has not 
moved much, and this may be taken as the eastern limit of 
the moving sheet. We don't of course know the extent of 
the ice sheet to the south-east. 
Depot A moved 608 yards in thirteen and a half 
months, which agrees closely with the 500 of movement 
observed by the Nimrod. 
We must take note of the direction of movement 
observed, for this may not represent the total movement. 
It may give the minimum, and this result is very startling 
in view of the sluggish land glaciers. 
Simpson suggests that the deposition of snow on the 
Barrier leads to an expansion due to the increase of weight. 
If it is 350 miles long and 400 feet thick, then the ratio of 
thickness to length is i to 5250. This can be adeqiiately 
compared to a sheet of cardboard ^ inch thick and the 
length of this hut (50 feet). 
The ice sheet can only move to the north. If we assume 
it moves 1000 yards, and that 175 square miles is the 
amount moved north, then the mass to be added to keep 
