will
run to the feeder whenever the. bell rings.
--Contributed by Dr. H. A. Dobson, Washington, D. C.

[Illustration: Will Open or Close Circuit as Desired]

** Homemade Disk-Record Cabinet [79]

Select some boards that have a nice grain and about 1 in. thick
and 12-in. wide. Cut the end pieces each 36-in. long and trim down
the edges so as to make them 11-3/8 in. wide. The top board is
made 28-in. long and full 12-in. wide. The three shelves are cut
25-in. long and the edges trimmed so they will be 11-3/8 in. wide.
The distance between the bottom of the top board and the top of
the first shelf should be 3 in. Two drawers are fitted in this
space, as shown in Fig. 1. A series of grooves are cut 1/4 in.
wide,

[Illustration: Cabinet Holding 32 Records]

1/4 in. deep and 3/4 in. apart on one side of the top and bottom
shelves, as shown in Fig. 2, and on both sides of the middle
shelf. The shelves should be spaced 9-5/8 in. for 10-in. records
and 5-5/8 in. for 6-in. records. A neat scroll design is cut from
a board 25 in. long to fill up and finish the space below the
bottom shelf.
--Contributed by H. E. Mangold, Compton, Cal.

** A Battery Rheostat [80]

In a board 7 in. long and 5 in. wide bore holes about 1/4 in.
apart, in a semicircle 2 in. from the bottom, and cut notches in
top end to correspond with the holes. From a piece of brass a
switch, C, is cut with a knob soldered on at the end. Nails for
stops are placed at DD. Two binding-posts are placed in board at A
and B. With about 9 ft. of fine iron wire attach one end to the
bottom of post A and run through first hole and over in first
notch to back of board and then through second hole and over
second notch and so on until E is reached, where the other end of
wire is fastened. Connect switch to post B.
--Contributed by Edmund Kuhn, Jr., East Orange, N. J.

[Illustration: Battery Rheostat]

** Automatic Time Switch [80]

This device may be used to either open or close the circuit at any
desired time. An alarm clock is firmly fastened to a wooden
bracket and provided with a small wood or metal drum, A, to which
is fastened a cord, B. The other end of the cord is tied to the
switch handle so that when the alarm goes off the switch is either
opened or closed, depending on whether the cord is passed over
pulley C or pulley D.

When the cord is passed over pulley C, as shown in Fig. 1, the
circuit will be closed when the alarm goes off, but