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 temperature 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 companions 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, 1835.
After eating our potato-less breakfast, we travelled across the intermediate tract to the foot of the Portillo range.