M. Andre de Luc on the Glaciers of the Alps. 17 



year 1817 to 1822, the glaciers of the Alps made further ad- 

 vances than at any preceding period. In 1821, and even as 

 late as June 1822, the Glacier des Bois made a considerable 

 descent, overturning trees, some of which were two feet in 

 diameter, and making so near an approach to habitations that, 

 in the month of June, it was not farther distant from the 

 nearest house than forty paces ; on the 8th of June, it was 

 only sixty-six feet distant, and in the month of August sixt}'- 

 two feet. These facts prove to us that the glacier had never 

 before advanced so far, for no one would have built a house at 

 so small a distance. The intense heat of the summer of 1822 

 caused the glacier to sink greatly and begin to retire. This 

 eflfect must have been produced in part by the abundance of 

 water flowing beneath the glacier, and rapidly diminishing its 

 substance. 



Let us now turn our attention to the Glacier des Bossons. 

 Previous to the year 1812, the lower extremity of this glacier 

 was surrounded with pines, the size of which indicated that 

 they must have had undisturbed possession of the soil for ages. 

 But in 1812, when a succession of six cold summers com- 

 menced, the Glacier des Bossons made successive advances, 

 both in length and breadth. This progress continued till 

 1818 ; all the trees were overturned, not only in front of the 

 glacier, but even on its sides. After having destroyed this 

 forest, the glacier covered the meadows, where it was per- 

 fectly obvious it had never been before, for neither moraines 

 nor stones had ever existed on these meadows. But in 1820, 

 and particularly in 1822, when the glacier retired considerably, 

 these meadows were left covered with stones, some of which 

 were blocks of great size. It has been observed, in general, 

 that surfaces which have been once occupied by glaciers, 

 lose their vegetable earth and become barren ; a circumstance 

 which affords another proof that the meadows of -which we 

 speak, and even the site of the forest, had never before been 

 covered by the glacier of the Bossons. 



Let us again revert to the upper glacier of the Grindel- 

 wald. This glacier advanced in 1817, and continued to do so 

 even in winter, till the autunm of 1822. On the preceding 

 summer, it was more advanced than it had ever been, for, in 



VOL, XXVIII. NO. LV. JANUARY 1840. B 



