8 AVALANCHES. 



the high valley of Engadin, in the country of the Grisons, and in the 

 same year eighty-four persons and four hundred head of cattle, in 

 Obergestelen, and twenty-three persons at Brieg, both situated in the 

 Canton of Wallis. In the same country the village of Briel was almost 

 entirely covered by an avalanche in 1827. 



Many thousands of strong trees are destroyed by these avalanches, 

 either by being broken off near the ground, or by being rooted up, 

 strewed to pieces, and thus precipitated into the valley. Where these 

 avalanches are of common occurrence, the inhabitants of the valleys 

 know the places where they come down, and by observing the changes of 

 the weather, they are able to foretel the time of their descent. The 

 sliding avalanches originate on the lower and less steep declivities, when 

 after a long thaw in spring, those layers of the snowy-covering which are 

 nearest the ground, are dissolved into water, and thus the bond is loos- 

 ened which unites the mass to its base. The whole snowy-covering of a 

 declivity then begins to move slowly down the slippery slope, and to 

 carry before it any thing which is too weak to withstand its pressure. 

 When an object does not directly give way to the mass, it is either borne 

 down by the snow accumulating behind it, or the whole mass divides and 

 proceeds in its course on each side of it. The ice or glacier avalanches 

 are nothing but pieces of ice, which formerly constituted a part of a 

 glacier, but, loosened by the summer heat, are detached from the principal 

 mass, and precipitated down with a noise like thunder. They are 

 commonly broken into small pieces by the rocks which they meet with in 

 their progress. When seen from a distance, they resemble the cataracts 

 of a powerful stream. In the valley of Grindelwald, Bera, they may 

 often be seen, and at the base of the Jungfrau, the thunder which 

 accompanies their fall is almost continually heard. They are less 

 destructive than the other avalanches, because they descend upon places 

 which are not inhabited. 



Occasionally the avalanches change their character in their progress. 

 When the declivity is not too great, and the ground under it not too 

 slippery, the mass of snow begins to slide, but arriving at a precipitous 

 descent, its velocity and its masses are considerably increased, and it 

 begins to roll. If in this stage of its course it meets a strong craggy 

 rock, the mass is instantly divided into innumerable small pieces, and 

 thus it appears at the end of its progress like a drift avalanche. 



These phenomena are commonly known by the name of avalanches 

 in France, but situate between the ranges of the Alps, they have the 

 names of lids, lits or lydts. In Italy they arecalled Lavina; in Germany, 



