Progress of Foreign Science, 161 



Vienna, inserted in the third number of the seventeenth volunne. 

 He coils round a glass tube or wooden cylinder, steel-wire cover- 

 ing the surface as with a continuous sheath. To one end of 

 this cylindric spiral, he applies the south or north pole of a 

 magnet, and draws it along the cylinder in a straight line, 

 parallel to the axis. In this way a magnet is formed, which 

 possesses the following properties : 



(a) Along its whole length, it has on one side the north, 

 and on the opposite side the south pole. 



(6) These transversal magnetisms are in every point of the 

 length of the wire-cylinder, equally strong. 



(c) Both of its ends exhibit on the contrary no particular 

 polarity, and they have no other magnetism than that which 

 belongs to every individual point of the whole length. Thus 

 the transversal magnet is in the same condition as the con- 

 junctive wire of the voltaic column, 



{d) If we hold this transversal magnet over a magnetic 

 needle, in the declination-plane, it repels exactly like the con- 

 junctive wire, the north pole of the needle to the right or to 

 the left, according as the effective north-pole of its transversal 

 magnetism lies to the left or to the right hand; and with 

 greater or less force, according to the strength of its magnet- 

 ism, even to 90 degrees. 



(e) If we draw the one pole of a magnet along this trans- 

 versal-magnet, in a spiral direction, the wire becomes magnet- 

 ized longitudinally ; the transversal magnetism disappears, 

 the two poles are found at the two extremities, and it now 

 resembles an ordinary magnetized steel wire. The longitu- 

 dinal and transversal magnetisms are not compatible with each 

 other, in their full exhibition. 



Besides diis transversal magnetism with single polarity, 

 magnets may be easily made, possessing several transversal 

 imagnetisms. Take four magnetic bars, about a quarter of an 

 inch thick ; provide a small disk of wood, with an aperture of 

 about an inch diameter in its centre, and four grooves, cut in 

 one face of the disk, leading from the circumference, inwards, 

 in these grooves the magnetic bars are to be fixed, with their 

 narrow edge outwards, and their ends projecting into the 

 aperture. Let a north pole alternate with a south pole in the 

 circle, so that the ends of the bars right opposite to each other 

 may be homologous ; and adjust the whole, so that they may 

 touch the circumference of a steel wire-coil, about half an inch 

 diameter. We then draw this spiral wire, through the opening 

 and between the four magnets, taking care that the cylindric 

 coil does not revolve on its axis, but that the direction of 

 each individual magnetic pole remains in the same plane with 

 the axis ; for, otherwise the wire would acquire the longitu- 

 dinal magnetism. Instead of the wire-coil, wc may take k 

 massive cylinder of steel. This will acquire, when treated in 



Vol. XIII. M 



