Together with Jens Wilken Hornemann, he traveled through large parts of Norway and carried out botanical investigations, collecting plants to be included in the plate work Flora Danica.

In 1814, he was appointed professor of national economy and botany at the newly founded Royal Frederick University in Christiania (now Oslo).

However, he never took up the position as he embarked upon travels abroad to establish contacts and keep abreast of the development of botanical gardens in Europe.

Buch planned to visit the volcanic Canary Islands and Madeira, and Smith eagerly seized the opportunity to participate in an expedition with the experienced scientist.

[4] Having learned geology from Buch in addition to discovering new plant species, Smith was approached by the Royal Society of London and asked to participate in a scientific expedition under Captain James Hingston Tuckey to determine whether the Congo River had any connection to the Niger basins of western and central Africa.

(1840) from Tenerife and the genus Christiana (Malvaceae: Brownlowioideae), discovered in Congo by Smith and described by Augustin Pyramus de Candolle in his Prodromus systematis naturalis regni vegetabilis (1824).