II. LOOPS.

If the wire, with its lines of force, be bent into the form of a

vertical circle 1-1/8 in. in diameter, and fixed in a glass plate,

some of the lines of force will be seen parallel to the axis of the

circle. If the loop is horizontal, the lines become points.

[Illustration: Fig. 14.]

[Illustration: Fig. 14a.]

Scientific American Supplement, No. 643, April 28, 1888 · 第 38 / 57 题