(B) Place the paper over it all, and sprinkle filings upon it to get the magnetic figure.
(C) Make a sketch of the resulting figure, and compare it with the figure made in [Exp. 33]. Why do the lines of force appear indistinct in the center of the ring and around it? (See [§74].)
68. Directions. (A) Arrange the two bar magnets, as in [Exp. 33], but with their two N poles an inch apart.
(B) Make the magnetic figure of the combination. Do the lines of force flow from one N pole directly to the N pole of the other? Do the particles of filings reaching out from one B M attract or repel those from the other B M?