292 H. C. RUSSELL. 
to make as some authorities demand? Were the Antaretic 
regions as large as the whole world, there would not be space to 
make the icebergs which we see in process of destruction in the 
ocean, if the origin of each iceberg was away back in pre-adamite 
days. 
When we come to look at these reports closely, we find the 
great majority of the icebergs are of moderate dimensions—five 
hundred to two thousand feet in extreme dimensions—and such 
icebergs might, I think, be formed in comparatively short periods. 
Slow as the motion of solid ice is known to be, it does makea 
measurable progress from year to year ; that progress depending 
upon the amount of snow, and the decline down which it is finding 
its way to the sea. But taking an average glacier, it progresses 
a mile in from twenty to thirty years, and therefore the great 
majority of icebergs of the dimensions just given could be made 
in comparatively short periods. Some are, however, very much 
larger, and the number of icebergs seem to be vastly greater in 
some years than in others. As an explanation of this it has been 
suggested that unusual falls of snow may account for it by acclerat- 
ing the motion of the ice; but I.think the circumstances forbid 
the acceptance of this view, because the motion of the glacier, 
as we have already seen, depends mainly on the declivity down 
which it is descending, and that does not alter, and the piling 
up of snow could not in one year cause such a marked increas? 
in the rate of flow as would be necessary to account for the 
enormous increase in number of icebergs which appear from time 
to time, as for instance in 1854 and 1891. _ 
There must evidently be a force sufficient to break off the ice- 
bergs which are slowly forming on shore, and to do it at irregular 
periods separated by many years. Such a force seems to reside 
in the volcanoes of the Antarctic continent, when they burst forth 
in eruption and earthquake, and so shake the foreshores, that the 
icebergs are broken off from the glaciers and set adrift to flost 
we know not where. 
Vinnie ae pee os 
