POPOCATEPETL AND IXTACCIHUATL—FARRINGTON. 87 
TABLE OF DETERMINATIONS OF ALTITUDE OF POPOCATEPETL. 



METERS. PEET. 
Pico Mayor (highest point) !...| 5,280 17,159 | Truquiand Craveri, 1855. 
W. side of crater. f 5,341 17,523 Heilprin, 1890. 
5,391 17,087 ° | Ponce de Leon, Trig. det. 1870. 
5,400 17,713 | Humboldt, Trig. det. 1803. 
5.406 17,730 | Almazan. 
5,420.4 | 17,784 | Sonntag, 1857. 
5,441 17,0510) Dirbeck, 1327. 
5,450.9 | 17,881 | Aguilera and Ordonez, 1894. 
5,450 L7,oo4 | Glennie, 1527. 
Espinazo del diablo!.......... 5,240.4 | 17,193 | Sonntag. 
E. side of crater. § 5,247 17,215 | Dollfus et als., 1865. 

My own ascent was made February 18-19, 1896. Having sought 
in vain in the City of Mexico for a companion, I concluded, hke Mr. 
Ober, to make the attempt ‘‘ alone with three guides.”’ 
I left the City of Mexico on the 17th, having previously tele- 
graphed Sr. Don Pedro de la Noriega at Ameca to have horses and 
guides ready for the following day. The morning excursion train on 
which I had intended to take passage for Ameca was unfortunately, 
for lack of patronage, not run, so that it was late in the day before I 
reached the town. This gave me less time than I wished for prepara- 
tion, but did not cause serious hindrance. After a good night’s rest 
at the hotel, and a delay of several hours caused by the desire of my 
guides to attend special services at the church, I was ready about 11 
A.M. to start. My mount was a small horse which proved tough and 
serviceable. My guide, Manuel, rode one still smaller, but an animal 
of wonderful endurance. Upon a pack-mule were placed sacks of 
barley for the horses, my own provisions and blankets, and the food 
for the guides—a bundle of ¢fortz//as. Driving the pack-mule in front 
of us we started off at a sharp trot under a tropical sun across the 
plain of Ameca. Behind us came the two Indian guides, on foot, 
one of whom carried my camera. 
For about an hour the road led over the almost level plain of 
Ameca, amid fields of maguey or century plant, and barley and corn. 
The road was like many of those in Mexico, sunken, being thus with 
a ditch at each side fenced from the fields. The section of the soil 
thus afforded showed it to be alluvial with almost no bowlders, the 
few showing being of the hornblende andesite common about Ameca. 
Here and there over the plain at intervals a tall dust-spout could be 
seen to form and whirl its way for some distance ere it was dissipated. 
I noted similar ones on other plains in Mexico and regarded their 
frequent formation as due to the ‘‘ pocket-like”’ character of the 
