around the south pole, and a series of simultaneous observations at eight or ten magnetic stations. A great English astronomer and physicist has calculated* that the mass of observations which are in progress will accumulate in the course of three years to 1,958,000. [footnote] *See the article on 'Terrestrial Magnetism', in the 'Quarterly Review' 1840, vol. lxvi., p. 271-312. Never before has so noble and cheerful a spirit presided over the inquiry into the 'quantitative' relations of the laws of the phenomena of nature. We are, therefore, justified in hoping that these laws, when compared with those which govern the atmosphere and the remoter regions of space, may, by degrees, lead us to a more intimate acquaintance with the genetic conditions of magnetic phenomena. As yet we can only boast of having opened a greater number of paths which may possibly lead to an explanation of this subject. In the physical science of terrestrial p 193 magnetism, which must not be confounded with the purely mathematical branch of the study, those persons only will obtain perfect satisfaction who, as in the science of the meteorological processes of the atmosphere conveniently turn aside the practical bearing of all phenomena that can not be explained according to their own views. Terrestrial magnetism, and the electro-dynamic forces computed by the intellectual Ampere,* stand in simultaneous and intimate connection with the terrestrial or polar light, as well as with the internal and external heat of our planet, whose magnetic poles may be considered as the poles of cold.** [footnote] *Instead of ascribing the internal heat of the Earth to the transition of matter from a vapor-like fluid to a solid condition, which accompanies the formation of the planets, Ampere has propounded the idea, which I regard as highly improbable, that the Earth's temperature may be the consequence of the continuous chemical action of a nucleus of the metals of the earths and alkalies on the oxydizing external crust. "It can not be doubted," he observes in his masterly 'Theorie des Phenomenes Electro-dynamiques', 1826, p. 199, "that electro-magnetic currents exist in the interior of the globe, and that these currents are the cause of its temperature. They arise from the action of a central metallic nucleus, composed of the metals discovered by Sir Humphrey Davy, acting on the surrounding oxydized layer."