The American Journal of Science and Arts (Volume 37) (Paperback)

Purchase of this book includes free trial access to www.million-books.com where you can read more than a million books for free. This is an OCR edition with typos. Excerpt from book: Art. IX.?Terrestrial Magnetism; byJ. Hamilton of Carlisle, Penn. In the 22d volume of this Journal 1 suggested the idea, that the magnetic poles coincided with the coldest points in the northern hemisphere, but did not assign the grounds for such a conclusion. In 1837, Dr. Brewster published his Treatise on Magnetism at Edinburgh, originally prepared for the Encyclopedia Britanica, which contains very full details of the latest researches on that subject. In the 42d page of this Treatise it is stated, " the discovery of two poles of maximum cold on opposite sides of the north pole of the earth, which was announced by Sir David Brewster in 1820, led him and other authors to the opinion, that there might be some connection between the magnetic poles, and those of maximum cold." The opinion advanced by Dr. Brewster, " that there are two poles of greatest cold in the northern hemisphere," it appears, was published in the 9th volume of the Edinburgh Transactions of 1821, and Dr. Dal ton in remarking on it, considers it as a probable supposition, and Mr. KupfTer in a memoir read in 1829 to the Russian Academy, explicitely adopts the opinion. Of all this I knew nothing when I wrote the letter above referred to in 1832, nor until I met with Dr. Brewster's Treastise published in 1837; but drew the inferences therein stated, from the views I entertained of the nature of light and heat, and from observing a certain correspondence of climate at similar distances from the magnetic poles. I regard light and heat in the common acceptation of these words, as not only material in their nature, but as compounds of other simple elements, and suppose the magnetic fluids to be two of those simple substances which enter into their constitution. From the refined nature of light and ...