28 MEXICO, CENTRAL AMERICA, WEST INDIES. 



scaled. The ascent is in fact relatively easy, thanks to the regularity of the slope, 

 although the porphyritic mass of Popocatepetl exceeds Mont Blanc by ahout 1,900 

 feet. The mean of eleven measurements yields 17,880 feet, or, according to Ponce 

 de Leon, 17,780 for the Mexican giant, which is consequently at least 820 feet 

 lower than its Xorth- American rival. Mount St. Elias. 



On the east slope the lower limit of the permanent snows is at 14,200 feet. 

 Here all the ruo-osities of the surface are filled with snow, which round the rim of 

 the crater is transformed to a crystalline mass 8 or 10 feet thick ; thus are deve- 

 loped a few small glaciers fissured by little crevasses. About the east foot of the 

 mountain are met a large number of scattered boulders, which should with great 

 probability be attributed to the action of much larger glaciers, which formerly 

 descended from the summits. 



Above the crater rise two chief summits, the Pico INlayor and the Espinazo 

 del Diablo, which rest on a sharp ridge where the explorer has to maintain his 

 equilibrium between two profound chasms. On one side the view stretches east- 

 wards to the hot lands dominated by the plateaux ; on the other yawns the crater, 

 a cavity over half a mile in circumference, and 250 feet deep. 



This cavity is fiUed with snow ; but jets of gas, which frequently shift their 

 place, melt the white mass round about the respiradero, that is, the orifice of the 

 crater. Thus are revealed from a distance those patches of a yellow gold colour, 

 ■which indicate the position of the sulphur deposits. The volcaneros, w^ho almost 

 daily come in search of the sulphur, are let down to the bottom of the crater in a 

 large basket, which is lowered and raised by means of a windlass erected on the 

 brim of the chasm. The annual yield is estimated at about fifty tons, and the 

 mineral is supposed to accumulate at the rate of a ton a day. A spring welling up 

 on the bed of the crater fills a lagoon, whose waters, according to report, reappear 

 in thermal fountains at the base of the mountain. Eruptions are rare, and have 

 been less violent during the present century than at the time of the conquest. 



North of Popocatepetl rises the less elevated but still lofty Ixtaccihuatl, or 

 «White Woman" (16,300 feet), which, however, is not a volcano, although much 

 dreaded by the natives, and made the subject of numerous popular legends. The 

 mantle of perennial snows clothing its craterless porphyritic cone is nowhere 

 pierced by any fumeroles. According to the Aztecs the two mountains were 

 divinities, Ixtaccihuatl being the wife of Popocatepetl, which now serves as a 

 meteorological indicator for the populations dwelling at its base. When the vapours 

 are a dense black colour, and roll away from the crater in great wreaths in the direc- 

 tion of the north, rain may be expected. But when the smoke sets southwards it 

 is a sign of approaching frosts and cold weather. If again the column of vapour 

 assumes a vertical direction, it is regarded as a forecast of high winds, or else of 

 earthquakes. Two or three hours before a thunderstorm bursts over the plain, 

 the crater is seen to discharge at intervals quantities of ashes and pumice. 



The two sister mountains which dominate the valley of Mexico stand at the 

 angle of the triangular bastion w^hich is formed by the central plateaux of Ana- 

 huac. In the neighbourhood of Tehuacan the Western and Eastern Sierra Madrés 



