 The first journey was from Acapulco to Mexico City, through what is now the Mexican state of Guerrero.The route was suitable only for mule train, and all along the way, Humboldt took measurements of elevation.When he left Mexico a year later in 1804, from the east coast port of Veracruz, he took a similar set of measures, which resulted in a chart in the "Political Essay", the physical plan of Mexico with the dangers of the road from Acapulco to Mexico City, and from Mexico City to Veracruz.