Remark.-Hermite has shown (Crelle, Bd.
Vi., Crelle, xlix.
Frobenius, on Bilinear Forms, Crelle, lxxxiv., and Berl.
Clebsch has shown, from purely analytical considerations (Crelle, lvi.); and then = Z d(?G, m), ?
Further state aid enabled him to visit Germany and France in 1825, and having visited the astronomer Heinrich Schumacher (1780-1850) at Hamburg, he spent six months in Berlin, where he became intimate with August Leopold Crelle, who was then about to publish his mathematical journal.
In 1829 Crelle obtained a post for him at Berlin, but the offer did not reach Norway until after his death near Arendal on the 6th of April.
This having fallen out of print, permission was sought by the editor of Crelle to reproduce it in the pages of that journal.
His papers, numbering over 100, were published principally in the Philosophical Transactions, Proceedings of the Royal Society, Quarterly Journal of Mathematics, Proceedings of the London Mathematical Society and Crelle, and one or two in the Comptes rendus of the Paris Academy; a list of them, arranged according to the several journals in which they originally appeared, with short notes upon the less familiar memoirs, is given in Nature, xxvii.