FLOODS IN SWITZERLAND. 139 



the clanger which had been so long impending over it. 

 But as the heat of the weather increased, the central 

 part of the barrier slowly melted away, until it became 

 too weak to bear the enormous weight of water which 

 was pressing against it. At length it gave way, so 

 suddenly and completely that all the water which re- 

 mained in the lake rushed out in half an hour. The 

 downward passage of the water illustrated, in a very 

 remarkable way, the fact that the chief mischief of 

 floods is occasioned where water is checked in its 

 outflow. For it is related that, * in the course of 

 their descent the waters encountered several narrow 

 gorges, and at each of these they rose to a great height, 

 and then burst with new violence into the next basin, 

 sweeping along forests, houses, bridges, and cultivated 

 land.' Along the greater part of its course the flood 

 resembled rather a moving mass of rock and mud than 

 a stream of water. Enormous masses of granite were 

 torn out of the sides of the valleys and whirled for 

 hundreds of yards along the course of the flood. M. 

 Escher relates that one of the fragments thus swept 

 along was no less than sixty yards in circumference. 

 At first the water rushed onwards at a rate of more 

 than a mile in three minutes, and the whole distance 

 (forty-five miles) which separates the valley of Bagnes 

 from the Lake of Geneva was traversed in little more 

 than six hours. The bodies of persons who had been 

 drowned in Martigny were found floating on the 

 farther side of the Lake of Geneva, near Vevey. 

 Thousands of trees were torn up by the roots, and the 



