A
small piece of wood, A, Fig. 1, is cut about 5 in. square, to the
center of which is attached a small piece of soft iron wire, such
as used for cores
[Illustration: Mechanical Table Talk]
of induction coils, about 4 in. long and bent in the form of a
hook at the lower end, as shown at B. This wire is attached to the
block of wood, A, as shown in Fig. 2. The end of the wire is
soldered to a small brass plate which is set in the block so it
will be level or flush with the top of the block and then fastened
with two screws. The block A is fastened to the under side of the
table with two screws. A small coil, C, is made by winding No. 24
silk or cotton covered wire around a small tube, either a piece of
glass, a short straw or a quill. The coil is made tapering as
shown without using wood ends. This coil is slipped over the wire
B previous to soldering it to the small brass plate. The ends of
the coil are connected to two binding-posts which are fastened to
the block A. A small lead weight weighing 2 or 3 oz. is hung on
the hook made in the lower end of the wire B.
When all connections are made, as shown in Fig.
Pages:
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340