TORREITTS OP THB HIGH ALPS. 27 



lime, 2 mfetres or nearly 7 feet thick, and 5 metres or 17 feet in height. The 

 breach, extending 25 mfetres or 83 feet in length, fell with a crash which was 

 heard more than 3000 mfetres or 2 miles off. It raised a cloud of dust 

 through which was seen the lavarlike stream making straight for the town." 



Another case, which shows how sudden these irruptions are, was this : — 

 " In 1837 the village des Grottes was encroached upon by a small torrent of 

 the third kind, which no one had ever feared. In an instant the cellars 

 and the tortuous streets of the village were inundated with mud and blocks 

 of stone. A great many cattle were smothered. With difficulty many 

 people escaped with life, and a child perished in a stable." 



The following additional facts, relative to the avalanche form taken by 

 the torrents, are given : — " At the bridge over the little torrent-stream of 

 Chaumateron, in June 1838, the road-labourer heard the precursory sound. 

 Aware of the danger he moved away. He had gone but a step or two when 

 he saw coming the torrent tumblmg over itself. It threw itself in one 

 mass over the bridge and broke it. The elevation of the roadway of the 

 bridge above the radier plate was 5 mtoes or 17 feet. 



" The village of Saint-Chaflfrey is traversed by a small torrent. The 

 bassin de riception is hollowed out of a bed of gypsum. It flows over a steep 

 declivity at the foot of solid banks, but not very high. At every rise or 

 swelling of the torrent it comes tumbling over itself like a ball, 8 metres 

 or 25 feet in height, and a portion of the hemisphere appears above the 

 banks. It is formed of liquid thickened with gypsum, and brings in its 

 train a great current of water, which tears along with violence, but following 

 ordinary laws. With these examples (says he) I stop. They might be 

 multiplied indefinitely, for they are renewed every year." 



My purpose in citing these details is, first, to make my readers acquainted 

 with the facts stated ; next, to give confidence in the man who could bravely 

 grapple with the question, — How shall such torrents be bridled and tamed ? 

 and beyond this, to give confidence in the application, to what may be con- 

 sidered as the torrents of a miU-lead in comparison with these, of measures 

 deemed, and proved by recorded results, to be sufficient to prevent so 

 much as the formation of torrents so irresistible in their might as these. To 

 this I have referred in the introduction, and I refer to it again. My fear, 

 as stated then, is that to many the statements will appear incredible, and 

 that thus the end and object I have in view will fail to be accomplished. 

 Statements of fact, far surpassing what may have come under the experience 

 or observation of a reader, ftiay arouse suspicion in regard to much besides 

 what may be stated in connection with what thus startles, and may call forth 

 resistance to the truth advanced. The rise of such incredulity may perhaps 

 be prevented, if I shew that these statements are in accordance with what 

 has been stated by others of what has come under their observation else- 

 where. To those who are conversant with the literature of the subject there 

 is nothing startling in such statements. Theories may be questioned, but 

 the facts are accepted. 



I shall afterwards have occasion to cite at some length the statements 

 made by M. de Mardigny in a Memoire sur les Inondations des Eivieres de 

 VArdeche; here I cite only one. Of the tributaries of the Ardfeche he tells 

 that they often hurl into the bed of that river "enormous blocks of rock, which 

 this river in its turn bears onwards and grinds down at high-water, so that 

 its current rolls only gravel at its confluence with the Rhone." 



