390 AIucella?ieous Inielltgence. 



reserved for Florence and Rome. These excavations will pro- 

 yide for Tuscany an important branch of industry and commerce. 



13. Bagne Lake and Glacier. — A description was formerly given 

 (v. 372 and vi. 166.) of the singular lake which had formed in 

 the valley of Bagne, in consequence of the blocking up of the 

 river Dranse by a glacier, and also of the immense destruction 

 it occasioned by overthrowing its barrier, and escaping at once 

 into the lands beneath it. Up to the year 1805, no glacier of 

 this kind existed, but a large one on the precipices above con- 

 tinually sent down blocks and masses of snow and ice, which 

 Were removed by the waters of the rivers. It was the cold years 

 succeeding 1805 that gave rise to the permanent formation of the 

 lower glacier, for the masses of snow that fell into the river were 

 so large that it had not the power to remove them, though it 

 found a passage by filtration through them ; and then succeed- 

 ing winters hardened and consolidated the whole until it gave 

 rise to the catastrophe already described. 



The event which then took place, did not remove the whole of 

 the lower glacier or barrier ; on the contrary, scarcely a twen- 

 tieth part was broken down, and the river remained forced from 

 its old bed, and bordered on one side by the glacier, which ac- 

 cumulated so rapidly, that, at the end of 1819, the barrier to the 

 passage of the river was almost as complete as before its break- 

 ing up by the weight of the lake. 



It became, therefore, an important object to prevent a repe- 

 tition of the former catastrophe, by the adoption of such means 

 as would diminish, or, at least, prevent the increase of the 

 barrier. Blasting by gunpowder was found inadmissible 

 from the difficulty of firing the powder at considerable depths 

 in the ice, and from the comparatively small masses removed by 

 this means. After much consideration and many trials, a mode 

 has been adopted and put in execution by M. Venetz, which 

 promises the greatest success. 



M. Venetz had remarked that the glacier could not support 

 itself where the river was of a certain width, but fell into it, and 

 was dissolved ; whereas, where the river was comparatively 

 narrow, the ice and snow formed a vault over it, and conse- 

 quently tended to the preservation of any portion falling from 

 the glacier above. Perceiving also the effect of the river in 

 dissolving the parts it came in contact with, he formed and exe- 

 cuted the design of bringing the streams of the neighbouring 

 mountains by a canal to Mauvoisin, opposite the highest part 

 of the glacier, where it touched that mountain. From hence it 

 was conducted, by wooden troughs, on to the glacier in a direc- 

 tion parallel to the valley. The water was divided into two 

 streams, one falling nearly on the one edge of the Dranse, and the 

 other on the other ; and having been warmed by the sun in it& 



