THE VISCOUS FLOW. 
149 
cession of explosive detonations and propagated waves. 
But it is only the lesser masses falling into deep waters 
which could justify the popular opinion. The enor¬ 
mous masses of the Great Glacier are propelled, step 
by step and year by year, until, reaching water capable 
of supporting them, they ai'e floated off to be lost in 
the temperatures of other regions. 
INDICATIONS OF VISCOUS FLOW. 
The frozen masses before me were similar in struc¬ 
ture to the Alpine and Norwegian ice-growths. It 
would be foreign to the character of this book to enter 
upon the discussion which the remark suggests; but it 
will be seen by the sketch, imperfect as it is, that their 
face presented nearly all the characteristic features of 
the Swiss Alps. The overflow , as I have called the 
viscous overlapping of the surface, was more clearly 
