Publisher's Synopsis
This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1871 edition. Excerpt: ...at Fig. 169. the middle of the bar. As it approaches either end, it is attracted more and more, and near the ends the attraction is much the strongest. Lay a piece of stiff drawing-paper upon a strong magnetic bar, and strew fine iron-filings over it. The particles of iron (Figure 169) arrange themselves in lines radiating from the poles, called lines of magnetic force, or magnetic curves. 300. The Forces at the Ends of a Magnet act in Opposite Directions.--Suspend a bar magnet by a string (Figure 170) so that it can turn freely. Bring Fig. 170. one end of a bar magnet near one Jj end of the suspended magnet, and the latter is drawn towards it. Reverse the ends of the bar magnet, and the end of the suspended mag ir A sr net is repelled. This shows that the forces at the ends of a magnet act in opposite directions. The ends of the magnet, or the points where the opposite forces reside, are called poles. 301. The Magnetic Needle.--A bar magnet poised or suspended so as to turn freely is called a magnetic needle. One of its poles will always point to the north, and is called the north pole. The opposite pole is called the south pole. 302. The Earth acts like a Magnet.--If a small needle which is free to move horizontally be placed upon a bar magnet, its south pole will always point towards the north pole of the latter. If a small dipping needle, that is, a needle which is free to move vertically, be placed above the middle of a bar magnet, it stands parallel with the bar magnet. If it be moved towards the north pole of the magnet, the south pole dips more and more towards the magnet. If it be moved from the centre of the bar magnet towards the south pole, its north pole dips in the same way. Now, a magnetic needle (301) points north and...
