he fortunately received a private collection of instruments, by means of which he delivered lectures before a numerous and educated audience on electricity, galvanism, and magnetism, heat, light, and combustion, in accordance, indeed, with the dynamic theory, which deduces all chemical effects from the same fundamental forces. At the same time, he published numerous German and Danish treatises, the most important of which were The Series of Acids and Bases (in Gehlen's Journal), and especially his Observations on the History of Chemistry, which is most intimately connected with his scientific career, and is remarkable for pointing out the development and general tendency of his mind.
Oersted's intellectual and deeply-interesting lectures, but especially the publication of his new experiments on the acoustic figures,[1] at length payed the way in 1806 for his obtaining the professorship of physics at the University of Copenhagen. His active nature was now fully occupied by numerous public and private lectures; he succeeded in considerably enlarging his collection of instruments, and he was indefatigable in making experiments; he became teacher at the Academy of Land Cadets; he delivered lectures for the adjutants of the general staff, and in 1809 he published his Manual of Mechanical Physics, which was considerably enlarged and altered in 1844. The appearance of the portion devoted to chemistry was delayed partly by his travels, partly by the annual advances of science. During this ardent and ever enthusiastic activity in his own science, which was constantly developing itself, he refreshed himself in his private life by intercourse with an intellectual and stirring circle of society, which included the first men of his time, among whom were his brother, Steffens, Oehlenschlager, and the witty poet and critic Baggesen, who was his opponent at a later period. By intercourse with these men he was kept in
- ↑ See the Dialogue on Tones, in the following pages.
