Caspar Wessel and the Complex Numbers

In 1797 a paper by the Norwegian surveyor Caspar Wessel was presented to the Royal Danish Academy of Sciences and Letters. In this paper he introduced the geometrical representation of complex numbers. From his surveying reports we know that he had the idea at least as early as 1787. A biography relating his mathematical paper to his work as surveyor under the auspices of the Academy will appear in a book, edited by Jesper Lutzen, and published by the Academy in 1998.