256 Dr Clark and Capt. SherwilVs Ascent of Mont Slanc. 



Markham Slierwill of Fontainbleau proposed to accompany 

 him in the expedition. 



On Monday the 25th of August, about 7 o'clock in the 

 morning, our travellers set out from Chamouni, accompanied 

 by seven guides, viz. Joseph Maria Coutet, who had already 

 been three times at the summit of Mont Blanc ; Simeon 

 Devuasson, Pierre Tairraz junior, both of whom had once 

 been on the summit, and Julian Devuasson ; Pierre Joseph 

 Simond ; Simeon Tournier, the youngest of the guides, was 

 twenty-six years old, and the oldest thirty-eight. 



Having arrived at Pierre Pointue, they quitted their mules, 

 and as soon as they reached the moraine of the glacier, they 

 spent a short time in breakfasting. Before they set out, Dr 

 Clark counted the pulses of several of the guides, and he 

 found that their acceleration varied from four to thirty pulsa- 

 tions in a minute. This acceleration did not appear to have 

 any proportion, either direct or inverse, to the muscular 

 strength of the individuals. 



When they had reached the Grand Plateau, the rays of 

 the sun were so scorching, that Dr Clark was obliged to take 

 off his spencer. He experienced in his face the most painful 

 smarting. He was very thirsty, and he frequently refreshed 

 himself by eating snow and some grains of raisins. His re- 

 spiration was not changed, but it was loaded. Captain Sher- 

 will experienced much nausea and oppression. Having sat 

 down on the ice to take some refreshment, they eat very little. 

 Simeon complained of a pain in his head. When they reach- 

 ed the Petits Mulets, the wind became strong and very cold ; 

 at last, at five minutes past three o'clock, they reached the 

 summit of Mont Blanc. 



The barometer was at 15 inches 9 lines, and ^ths. At 

 St Bernard, at the same time, it stood at 21 inches, 1 line, 

 T 7 ths; and at Geneva, at 27 inches, lines, and ±§ths. The 

 thermometer exposed to the sun stood at half a degree below 

 zero, whereas, at Chamouni, in the shade, it reached 14°. At 

 two o'clock in the afternoon, the thermometer rose at St Ber- 

 nard to 10° below zero, and, in the Botanic Garden at Gene- 

 va, to 19°. 



Dr Clark experienced a difficulty of breathing, even when 



11 



