The elements of the Earth's magnetism for the Epochs 1600, 1650, 1700, 1780, 1842 and 1885, and their secular changes derived from observations calculated using the coefficients of the Gaussian "General Theory of Earth's Magnetism"

After a historical review of the theory of the Earth's magnetism, the author indicates how the theory may be improved and gives results of his own calculations for the Epoch 1842