342 OCCUPATIONS OF THE TRAVELLERS. 
purpose of arranging their botanical and geological 
collections, calculating the barometrical and _ trigo- 
nometrical measurements which they had made, and 
_ sketching the plates of the Geological Atlas which 
Humboldt proposed to publish. They also assisted 
in placing a colossal equestrian statue of the king, 
which had been cast by a native artist. In January 
1804 they left Mexico with the intention of examining 
the eastern declivity of the cordillera of New Spain. 
They also measured the great pyramid of Cholula, 
an extraordinary monument of the Toltecks, from 
the summit of which there is a splendid view of the 
snowy mountains and beautiful plains of Tlascala. 
It is built of bricks, which seemed to have been 
dried in the sun, alternating with layers of clay. 
They then descended to Xalapa, a city placed at 
an elevation of 4138 feet above the sea, in a de- 
lightful climate. The dangerous road which leads 
from it to Perote, through almost impenetrable fo- 
rests, was thrice barometrically levelled by Hum- 
boldt. Near the latter place is a mountain of ba- 
saltic porphyry, remarkable for the singular form of 
a small rock placed on its summit, and which is 
named the Coffer of Perote. This elevation com- 
mands a very extensive prospect over the plain of 
Puebla and the eastern slope of the cordilleras of 
Mexico, which is covered with dense forests. From 
it they also saw the harbour of Vera Cruz, the castle 
of St Juan of Ulloa, and the seacoast. 
Before following our travellers across the Atlantic, 
it may be useful to present a sketch of the valuable 
observations recorded in Humboldt’s Political Es- 
say on the Kingdom of New Spain, and which are 
in part the result of his researches in that interest- 
ing country. 
