e side of each of these pieces and tin
them well with solder. Place the two tinned surfaces just treated
in contact with each other and heat them until the solder on their
surfaces melts and then allow them to cool. A better way would be
to clamp the two thin pieces between two heavy metal pieces, and
then heat the whole to such a temperature that the solder will
melt, and then allow it to cool. This last method will give more
satisfactory results than would be obtained if no clamps are used,
as the thin metal pieces are liable to bend

[Illustration: Support for Couple, and Needle-Mounting Strip]

out of shape when they are heated, and as a result they will not
be in contact with each other over their entire surfaces. After
these pieces have been soldered together forming one piece, which
we shall for convenience speak of as the couple, two small holes
should be drilled in one end to be used in mounting it, and a
notch cut in the other end, as shown in Fig. 2.

Cut from some thin sheet brass, about 2/100 in. in thickness, two
pieces, 1/4 in. wide and 1/2 in. long. Bend these pieces of brass
over a piece of hatpin wire, thus forming two V-shaped pieces. Cut
off a piece of the hatpin, 5/8 in. long, and fasten it across the
notched end of the couple by means of the U-shaped piece of brass,
which should be soldered in place as shown in Fig. 3. All
superfluous solder should then be cleaned from the couple and the
steel pin. Now bend the couple so as to form a perfect half
circle, the brass being on the inside.

The base upon which this couple is to be mounted should be made as
follows: Obtain a piece of brass, 7 in. long, 3/4 in. wide, and
1/4 in. thick. In this piece drill holes, as indicated in Fig. 4,
except A, which will be drilled later. Tap the holes B, C and D
for 1/8-in. machine screws.

Cut from some 1/8-in. sheet brass a piece, 1-7/8 in. long and 3/4
in. wide, to be used as a support for the couple. In one end of
this piece drill two small holes, as indicated in Fig. 5, and tap
them for 3/16-in. machine screws. In the opposite end cut a slot,
whose dimensions correspond to those given in Fig. 5. Now bend the
piece, at the dotted line in Fig. 5, into the form shown in Fig.
6, making sure that the dimension given is correct. This piece can
now be mounted upon the piece shown in Fig. 4, by means of two
brass machine screws placed in the holes B. The slot in the
support for the couple will permit its being move