ASCENT OF MOXT BLANC. 91 



with them six candles, which they burned one hour. These 

 on returning to Chamonix, they weighed, and, after burn- 

 ing there another hour, weighed again. The loss of weight 

 in each instance was the same. This was a surprise, since 

 the light of the candles was much feebler on the moun- 

 tain than in the valley. The sound of a pistol was found 

 to be short, like the pop of a champagne cork. On this 

 occasion, posts were planted in the snow at several sta- 

 tions, one of which was the summit. To these, register- 

 ing thermometers were attached, for the purpose of mark- 

 ing the extremes of temperature during the year. Others 

 were planted in the snow. In 1860 Professor Tyndall 

 made efforts to ascend to the summit to examine his ther- 

 mometers, but was repelled by the " execrable weather." 

 In 1861 he succeeded. The post remained on the sum- 

 mit, but the thermometers were broken.* He states, how- 

 ever, that a thermometer left at the summit of the Jar- 

 din during the winter of 1858 recorded a minimum tem- 

 perature of eight degrees below zero. 



Life is not wholly extinct in these glacial solitudes. 

 On the most elevated rocks, but a few hundred feet be- 

 neath the summit, are found certain species of mosses and 

 lichens, and even microscopic animals. There is also an 

 insect which makes its home upon the glaciers, and hides 

 in the crevices and pores which permeate their mass. 



I must not leave Mont Blanc without giving briefly 

 the story of Balmat. De Saussure had awakened among 

 the cantoniers of Chamonix a lively interest in the dis- 

 covery of a route to Mont Blanc. He had offered a re- 

 ward to the first who should succeed. Jacques Balmat 

 entered into a lively sympathy with the aspirations of 

 * Tyudall, Hours of Exercise in the Alps, p 58. 



