Popular Science Monthly
��465
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���The Purple Lines Say ."This Envelope Has Been Steamed"
��How to Safeguard Mail Against
Meddlers
\KM an indelible [)enril and make
light lines — as shown in drawing — on
the back of the
envelope. Do not
wet pencil when
making the lines,
and it is not
necessary to bear
heavily on the
pencil ; for if the
envelope should
be steamed the
lines made with
the indelible pencil will turn to a bright
purple and remain plainly visible as
shown in the illustration.
A Substantial Home-Made Jack
A SUBSTANTIAL jack of consider- able lifting power is made with two pieces of 2 by 4 or 2 by 6 hardwood, two bars of steel or iron and a few bolts.
Cut one piece of the 2 by 4 about two or three feet long, according to the height desired for the jack. Cut another piece about 12 ins. long for the base, and fasten to the end of the upright piece, as in Fig. i, by nailing or by mor- tising. Now bore 3xj-in. holes near the edges of the upright on each side about 3 ins. apart and staggered as shown in Fig. I. Put 3.4-in. bolts in these holes with washers on both ends and screw nut up tight. It is best to use two nuts on each bolt.
Fig. 2 is a sectional side \'iew of the upright, showing the bolt through the timber with two nuts holding it in place.
One should be about 4 ft. long
��Procure two bars.
���Fig. 1
This Jack Will Not Kick or Cut Into the Object Lifted
��for the lever. In this cut a notch about 4 inches from the end. The other bar is about two ft. long, with a chisel point on one end. An elbow bolt or large staple is placed near the top for the short bar to pass through to prevent the jack from kicking
��under a load. A 4-in. block is now cut and placed on top of the upright bar to prevent the bar cut ting in to the object being lifted. The lever bar with upright bar set in notch to prevent slipping is worked up from the nuts on one boll to those on the bolt just above, as in Fig. i. Dotted lines show different positions of lever bar in operation. — Robt. F. Stayton.
A Case for Miniature Lamps
PROCURE two pieces of wood 2 ins. by 6 ins. by ^ in. Draw a line lengthwise through the center and then mark off every 3,4 in. on this line.
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��Fig. 2 C ovf r
��Diagram Showing Parts of Box Finished and Ready for Assembling
Drill holes with a bit the size of the lamp's base and drill them deep enough to allow the lamp to rest in, as in Fig. i.
Take the other piece of wood and measure ^ in. from the edge on all sides, making a rectangle which is to be dug out to a depth of yi in. This is shown in Fig. 2.
Ne.xt place the two together and fasten a small hinge to one end and a catch to the other end. The case is now complete except for sandpapering and painting. — Ch.\rles. W. Christ.m.v.v.
���The Case Complete with Lamps in Posi- tion in Their Sockets
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