Forchhammer then joined Hans Christian Ørsted and Lauritz Esmarch in their mineralogical exploration of Bornholm, and took a considerable share in the labors of the expedition.

In 1820 he obtained his doctorate by a chemical treatise De mangano, and immediately after set out on a journey through England, Scotland and the Faroe Islands.

In 1850 he began with Japetus Steenstrup and Jens Jacob Asmussen Worsaae various anthropological publications which gained a high reputation.

As a public instructor Forchhammer held a high place and contributed potently to the progress of his favorite studies in his native country.

He interested himself in such practical questions as the introduction of gas into Copenhagen, the establishment of the fire-brigade at Rosenborg[3] and the boring of artesian wells.

[2] In 1865, Johan Georg Forchhammer conjectured that the ratio of major salts in samples of seawater from various locations was constant.

[2] Forchhhammer's theory was proven correct in 1884 by Prof William Dittmar following extensive analysis of sea-water samples taken during the Challenger expedition.