312 ALEXANDER VON HUMBOLDT. 



furnished no security against being precipitated into the loose 

 snow beneath. 



' The sloping surface of snow extended to such a distance 

 that light pieces of dolerite (the only substance at hand), 

 when rolled down the incline, were lost sight of before reach- 

 ing any resting-place. . . . 



4 The rock became more friable, and the ascent increasingly 

 difficult and dangerous. At certain places where it was very 

 steep, we were obliged to use both hands and feet, and the 

 edges of the rock were so sharp that we were painfully cut, 

 especially on our hands. In addition to this, I had for some 

 weeks been suffering from a wound in my foot, caused by the 

 repeated attacks of the Niguas l (Pulex penetrans), which had 

 been greatly aggravated by the fine pumice dust to which I had 

 been exposed while taking measurements in the Llano de Tapia. 

 The loose position of the stones upon the . narrow ridge neces- 

 sitated extreme caution, since many masses that appeared to be 

 firmly attached proved to be only imbedded in sand. 



' We advanced all the more slowly, as every place that seemed 

 insecure had first to be tested. Fortunately, the attempt to 

 reach the summit of Chimborazo had been reserved for our 

 last enterprise among the mountains of South America, so 

 that we had gained some experience, and knew how far we 

 could rely on our own powers. It is a peculiar characteristic of 

 all excursions on the Andes, that beyond the line of perpetual 

 snow Europeans are always left without guides just at the point 

 where, from their complete ignorance of the locality, help is 

 most needed. In everything Europeans are left to take the 

 lead. 



' We could no longer see the summit, even by glimpses, and 

 were therefore doubly anxious to ascertain how much of the 

 ascent had still to be accomplished. We opened the tube 

 barometer at a spot where the ridge was wide enough to allow 

 two persons to stand side by side in safety. We were only 

 at an elevation of 17,300 feet, therefore scarcely 200 feet 

 higher than we had attained three months previously upon 

 the Antisana. 



1 The Sand-flea [Chigoe], an insect which, by burrowing beneath the skin 

 and depositing its eggs, produces swelling and inflammation. 



