1 < 
X89S 
Mount 
Orizaba 
2,000, 3,000 or 8,000 feet high above the 16,000 feet level exactly like 
the column of steam ascending from the smoke-stack of a standing locomo¬ 
tive on a cold calm morning. The same rounded form and slightly larger 
top suggested a similar foroe from below. 
It is at the time that these cloud columns form that the whirl¬ 
winds carrying high dust columns begin their fantastic marches across 
the sandy plain below and that the two are result of one and the same 
cause is certain. 
i 
The day that I ascended Popocatapetl and Orizaba a southwest wind 
was blowing* On Izt. a southeast wind blew and that day the dust columns 
and cloud columns were not observed. The other two days they were seen 
as noted. 
On April 28th I returned to Chalchicamula and remained there packing 
and making ready until May 2nd. 
On this latter date I left and proceeded by the mule-line R.R. from 
' 
Esperanza to Tehuacan, Puebla, It is a distance of 30 miles nearly 
south and mainly downhill. The car was divided into compartments into 
which a lot of us were crowded and then away we went, the mules at a 
gallop. Finally the track spread and we were derailed* thereupon every¬ 
one had to get off and by lifting and pushing managed to get the machine 
back on the track again. 
About 10 miles south of Esperanza we entered a canon between the 
limestone hills that we had skirted to the west thus far and the warmer 
climate of the descent was quickly shown by the appearance of large 
numbers of palmettoes with a species of tall slender-stemmed yucca that 
resembled the palm very closely at a distance. A little further down 
the oanon and many remarkable barrel-shaped cacti T»gan to appear in 
large scattered groups over the hillsides. These cacti are ribbed 
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