346 
PORTILLO PASS 
CHAP. 
f 
tainous country, intermediate between the two main ranges, 
and then took up our quarters for the night. We were now 
in the republic of Mendoza. The elevation was probably not 
under 11,000 feet, and the vegetation in consequence exceed¬ 
ingly scanty. The root of a small scrubby plant served as 
fuel, but it made a miserable fire, and the wind was piercingly 
cold. Being quite tired with my day’s work, I made up my 
bed as quickly as I could, and went to sleep. About midnight 
I observed the sky became suddenly clouded : I awakened 
the arriero to know if there was any danger of bad weather ; 
but he said that without thunder and lightning there was no 
risk of a heavy snow-storm. The peril is imminent, and the 
difficulty of subsequent escape great, to any one overtaken by 
bad weather between the two ranges. A certain cave offers 
the only place of refuge : Mr. Caldcleugh, who crossed on this 
same day of the month, was detained there for some time by 
a heavy fall of snow. Casuchas, or houses of refuge, have not 
been built in this pass as in that of Uspallata, and therefore, 
during the autumn, the Portillo is little frequented. I may 
here remark that within the main Cordillera rain never falls, 
for during the summer the sky is cloudless, and in winter 
snow-storms alone occur. 
At the place where we slept water necessarily boiled, from 
the diminished pressure of the atmosphere, at a lower temper¬ 
ature than it does in a less lofty country ; the case being the 
converse of that of a Papin’s digester. Hence the potatoes, 
after remaining for some hours in the boiling water, were nearly 
as hard as ever. The pot was left on the fire all night, and 
next morning it was boiled again, but yet the potatoes were 
not cooked. I found out this by overhearing my two com¬ 
panions discussing the cause ; they had come to the simple 
conclusion “ that the cursed pot (which was a new one) did 
not choose to boil potatoes.” 
March 22 nd .—After eating our potato-less breakfast, we 
travelled across the intermediate tract to the foot of the Portillo 
range. In the middle of summer cattle are brought up here 
to graze ; but they had now all been removed: even the 
greater number of the guanacos had decamped, knowing well 
that if overtaken here by a snow-storm, they would be caught 
in a trap. We had a fine view of a mass of mountains called 
