After graduation he was awarded a grant from the state treasury to conduct scientific research in Iceland, a project which he worked on from 1839 to 1842. He continued to pursue his interest in the natural history of Iceland, and to work on "Fjölnir" throughout his life, dividing his time between Denmark and research trips to Iceland. It was in "Fjölnir" that many of his poems and essays first appeared. Jónas also worked as a translator of foreign material, including scientific works. In these can be found many of the Icelandic words coined by Jónas. One of these, for an example, is "reikistjarna", meaning planet. This is a compound word from the verb "að reika" (to wander) and the noun "stjarna" (star).