or not at all, and the

 

or not at all, and the

The scales which are separated from the surface of red-hot iron when hammered, and the particles Coach Factory Outlet of burnt steel that are produced from the collision of a flint and steel, are attracted by the magnet nearly as well as pieces of good iron that equal them in bulk. The black C3lx of iron is attracted very weakly. The red calx, or rust, whether it be produced by the action of acids, of fire, or by exposure to the atmosphere, is attracted very little; but it nevtr becomes quite insensible of the magnet's action, though it be repeatedly washed and purified. It is observable, that a quantity of iron is attracted with the least force when reduced into the smallest bits, or finest powder. The ores of other metals are generally, though weakly, attracted by the magnet, thus indicating that they contain some iron: such are the ores of lead, of tin, and of copper. Native cinnabar is likewise attracted; but the factitious cinnabar is not. Of the pure metals, zinc, bismuth, and particularly cobalt, as well as their ores, are almost always attracted by the magnet. Antimony, vnlefs it be first exposed to a gentle fire, is not attracted. Arsenia is not attracted at all. A certain fort of bismuth possesses a singular property of being repelled on every side by the magnet. The other minerals, besides the metallic, are almost all attracted by the magnet, at least after having been exposed to the action of fire. Of the pure earths, the calcareous is least, or not at all, and the siliceous the most frequently, attracted.There are also several sorts of heavy, shining, opaque, black, or dark chocolate-coloured, sand, most of which, if not all, are iron ores, which are suYceptible of magnetism. Of this kind is the dark-brown sand in emery; we may also refer to this class most brass, and several other metals, and brick's that have been much burnt in the Are. The magnetism of these is probably owing to a small quantity of iron mixed with them. What is in the Coach Factory Outlet Online brass, Mr. Michell conjectures, may come from the lapis caLaminaris, which is said to Coach Outlet Online have often a small mixture of iron in it; but Mr. Arderon, who succeeded in giving magnetism and polarity to brass, has doubts as to the mixture of iron with brass. As we think this gentleman's experiments and remarks very curious, we (hall give the substance of ? them from the Phil. Trans. vol. 1. p. 774.AbstraB. os a Letter from Mr. William Arderon, F.R.S. to Mr. Henry Baker, F.R.S. on tie giving Magnetism and Polarity to Coach Factory Store Brass. Communicated by Mr. Baker j and-read before the Royal Society, November 16, 1758. Dear Sir; For some-time past I have been making experiments on the magnetism of brass ; and, amongst many pieces that I have tried, find several that readily attract the needle ; but whether they have had this property originally, or have received it by hammering, filing, clipping, or any other such-like cause, I cannot yet determine. I have a very handsome compass-box made of pure brass, as far as I can judge; the needle being taken out, and placed upon a pin fixed properly in a board, and clear of all other magnetics, the box will attract this needle at half an inch distance; and, if suffered to touch, will draw it full 90 degrees from the north or south points; and I think those parts of the box marked north and south attract the strongest. The cover of the box also attracts the needle nearly as much as the box itself.As to your supposition, that iron may be mixed with the brass, I do not know; but I have been informed it cannot be, as brass fluxes with a much less degree of heat than iron, and iron naturally swims on fluid brass. Besides, many of the specimens of brass I have tried were new as they came from the mill, where they were wrought ijito plates, and I Coach Factory presume were not mixed; yet these I have given the magnetic virtue to, when they had it not; and some pieces ot brass, which naturally attract the needle, seem to the eye as fine a bright yellow as any other, ,Aud are as inallea.ble as any I ever met with.Pieces of brass without any magnetic power, by propfrl/ hammering and giving them the double touch, Coach Diaper Bag Outlet after Mr. Michell's method.