Popular Science Monthly 



465 



T 



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. 



Pi* »fLtmpiB*te 



..ft-* -V- > 



Fig. 1 



I 



A 



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 



