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Download or read book Philosophical Magazine and Journal of Science, Vol. 27 written by David Brewster and published by . This book was released on 2015-09-27 with total page 602 pages. Available in PDF, EPUB and Kindle. Book excerpt: Excerpt from Philosophical Magazine and Journal of Science, Vol. 27: New and United Series of the Philosophical Magazine, Annals of Philosophy, and Journal of Science, July-December, 1845 IN two former communications to the Philosophical Magazine respecting the magnetic characters of metals generally and the temperatures at which they respectively lost or gained the powers of magnetic induction, I said that iron and nickel were the only metals which had this power, and that I could not find it in pure cobalt. In this I was in error; cobalt has this property in common with iron and nickel, as others have said. I have sought for the piece of cobalt on which I experimented and believed to be pure, but cannot find it, and am now unable to ascertain the cause of my error, though not too late to correct it. By favour of Dr. Percy and Mr. Askin I have recently experimented with two fine pieces of pure cobalt prepared by the latter, both being well-fused and perfectly clean masses. This metal becomes strongly magnetic by induction, either of a magnet or an electro-current, and can easily be made to lift more than its own weight. Like soft iron and nickel, it does not retain its magnetism when the inducing influence is removed. It was to me a point of great interest to ascertain whether, and at what temperature, cobalt would lose this power and become as the unmagnetic metals. To my surprise I found this to be very high, not merely much higher than with nickel, but far above that required for iron or steel, and nearly approaching the temperature of melted copper. That for iron is a moderate red heat, and that for nickel the temperature of boiling oil only. About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works.