For family reasons he was forced to return to Caracas, where he continued studies at the Universidad Central de Venezuela, where he majored in natural sciences under the leadership of Adolf Ernst.

The following year, he participated in the preliminary studies for the construction of a major railroad between Caracas and Valencia with extension to San Carlos.

In 1887 he accompanied the Venezuelan chemist Vicente Marcano on a scientific expedition to the upper Orinoco river, sent by President Antonio Guzmán Blanco.

The trip provided geographical positions and a collection of plants and archaeological objects found today in the US and Germany.

He was in charge of the geographical and botanical part, which began the work of measuring and triangulation of the mountain ranges and sites and cities between Valencia and Caracas.

[4] The following species of plants are named after him: Jahn wrote 41 works between scientific books and pamphlets, and 52 articles for newspapers and magazines, including: As of this edit, this article uses content from "The History of Alfredo Jahn", which is licensed in a way that permits reuse under the Creative Commons Attribution-ShareAlike 3.0 Unported License, but not under the GFDL.