FROM SANTIAGO TO MENDOZA BY THE USPALLATA PASS. 9 



attempt was made to bribe the officer in charge, but without eifect ; and I inferred from the con- 

 versation between the smuggler and my arriero that he would be assassinated, as one of his 

 predecessors had been, for being too honest. 



The hospitality of the arrieros appears to be worthy of remark. Several men stopped here 

 by our fire, as elsewhere, to warm themselves, chat or smoke, and there was invariably prepared 

 for them, without asking, the best meal our fellows could offer ; and as this attention was 

 received as a matter of course, I conclude it is a general custom. 



On the 24th, after finishing work, I rode back to the Inca's Bridge to examine it more fully, 

 and to bathe ; the latter being very necessary, as I had, by advice, allowed the dirt and grease 

 to collect on my face and hands to prevent them from chaj)ping. 



Mr. Darwin says that the bridge was formed by the stream breaking through underneath; 

 but without pretending to controvert his opinion, appearances justify the belief that it was 

 formed by the concretion of the water from several calcareous springs in the hill-side, which 

 may have gone on forming shelf after shelf, until they reached across. Such a process is now 

 going on. 



The length of the bridge is near sixty feet, its width fifty at the northeast end, and seventy 

 at the southwest; and its height above the river is about forty feet. On a shelf of rocks under 

 it are two boiling springs, which have been hollowed out so as to form baths. The water of 

 these has a temperature of 97° Fahrenheit, and tastes like soda-water: the arriero said it was 

 purgative ; but I drank a quantity, and experienced no other efi"ect than increased appetite. 

 While bathing in the spring, I occasionally got my face into the vapor jetting out with the 

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