e main top board
M, 8-1/2 in. wide and only 7/8 in. thick, which is fitted into a
1/2/-in. rabbet int back of the board M. Thes boards form the top
of the bench, and are fastened to the top pieces of the supports
with long screws. The board E is 10 in. wide and nailed to the
back of the bench. On top of this board and at right angles with
it is fastened a 2-1/2-in. board, F. These two boards are 7/8 in.
thick and 3-1/2 ft. long. Holes are bored or notches are cut in
the projecting board, F, to hold tools.

Details of the vise are shown in Fig. 3, which is composed of a 2
by 6-in. block 12 in. long, into which is fastened an iron bench
screw, S. Two guide rails, GG, 7/8 by 1-1/2 in. and 20 in. long,
are fastened into mortises of the block as shown at KK, and they
slide in corresponding mortises in a piece of 2 by 4-in. pine
bolted to the under side of the main top board as shown at L. The
bench screw nut is fastened in the 2 by 4-in. piece, L, between
the two mortised holes. This piece, L, is securely nailed to one
of the top cross pieces, C, of the supports and to a piece of 2 by
4-in. pine, P, that is bolted to the under sides of the top boards
at the end of the bench. The bolts and the bench screw can be
purchased from any hardware store for less than one dollar.

** Forming Coils to Make Flexible Wire Connections [443]

When connections are made to bells and batteries with small copper
wires covered with cotton or silk, it is necessary to have a coil
in a short piece of the line to make it flexible. A good way to do
this is to provide a short rod about 3/16 in. in diameter cut with
a slit in one end to hold the wire and a loop made on the other
end to turn with the fingers. The end of the wire is

[Illustration: Forming Wire Coils]

placed in the slit and the coil made around the rod by turning
with the loop end.

** Photographing the North Star [443]

The earth revolving as upon an axis is inclined in such a position
that it points toward the North Star. To an observer in the
northern hemisphere the effect is the same as if the heavens
revolved with the North star as a center. A plate exposed in a
camera which is pointed toward that part of the sky on a clear
night records that effect in a striking manner. The accompanying
illustration is from a photograph taken with an exposure of about
three hours, and the trace of the stars shown on the plate by a
series of concentric circles are due to the rota