SCENERY OF SWITZERLAND. 
1 16 
blue veins projecting somewhat beyond the whiter 
ice. This structure is very common, though present- 
ing different degrees of perfection in different glaciers, 
and different parts of the same glacier. It is rendered 
the more conspicuous, because the fine particles of 
dirt are naturally blown, and washed into the furrows. 
The veins are often oblique, in many cases trans- 
Fig. 28. — Section of Icefall, and Glacier below it, showing origin of 
Veined Structure. 
verse, in some longitudinal, and in others vary in 
different parts of the glacier. 
Here also we owe, I think, the true explanation 
to Tyndall. We will begin with the oblique veins, 
which are most marked at the sides, and fade away 
