92 M. Boussingault's Account of 



same height the breathing is more impeded on the snow than 

 on the rocks. I shall afterwards endeavour to explain this. 



We soon reached a black rock, which was elevated above the 

 ridge upon which we advanced. We still continued to ascend 

 for a time, but not without great fatigue, caused by the slight 

 consistence of the snow, which continually gave way under us, 

 and in which we often sank to the knees. Notwithstanding all 

 our exertions, we were soon convinced of the impossibility of 

 advancing farther ; for beyond the black rock the moveable 

 mass had a depth of more than four feet. We placed ourselves 

 on a block of trachyte, which resembled an island in the midst 

 of a sea of snow. We were at a height of 5115 metres. The 

 temperature of the air was 2°.9 cent. It was half past twelve 

 o"'clock. After all our fatigues, we had only attained a height 

 of 307 metres above where we commenced our first^ journey. 

 At this point I filled a flask with snow, in order to exatQinu 

 chemically the air contained in its pores, and of this I shall af- 

 terwards speak. 



In a few minutes we had returned to the place where we had 

 left our mules. I employed a few minutes in examining geo- 

 logically this part of the mountain, and collecting a series of the 

 rocks. At half-past three o'clock we commenced our journey 

 downward, and arrived at our farm at six o'clock. 



The weather had been delightful. Chimborazo had never 

 appeared to us so majestic ; and after our fruitless journey we 

 could not contemplate it without regret. We now resolved to 

 attempt the ascent from the steepest side, that is the side to- 

 wards Arenal. We knew that it was on that side that Humboldt 

 had ascended. The limit had been pointed out to us from Rio- 

 Bamba to which he had reached ; but we found it impossible 

 to obtain exact information as to the route he had pursued. 

 The Indians who had accompanied this intrepid traveller were 

 dead. 



Next morning at seven o'clock we proceeded towards Arenal. 

 The sky was remarkably clear. To the east we saw the cele- 

 bi'ated volcano of Sangay, which lies in the province of Macas, 

 and which La Condamine had seen in a state of constant erup. 

 tion. As we advanced, the ground became distinctly more 

 elevated. In general, the trachytic plateaus at the foot of the 



