bottom.Slip an empty test tube into each hole in the top andthroughthe hole
directly below it.Ifyou traced the holes correctly, the tubes will fit. Cover the
surfacesofyour test tube rack withaluminumfoil to make it last longer. You
will need several of these racks, and you will want to replace them as soon as
they become wet or contaminatedwith chemicals.Ifyou have test tubes of
morethanone size, you will have to find different boxes to fit the various sizes.
How to Make a Wire Gauze Pad.Fromaluminumscreening (the kind used
insummerwindow screens) cut a 5-inch square. With adarkpencil or a piece
ofchalk,measure!ofan inch in from each side and draw a square.
Measure!an inch in from each side of thesquareyoujustdrew, and draw a
second square. Now, using a metal or metal-edged ruler as a guide, fold in the
screening in the outside square. Do this on all four sides. Aftermakingthe first
fold, and still using the ruler as a guide, fold in on the second line. You may
find it difficult to manage the corners.Ifso,tapthem gently with ahammer.
Now you have a wire gauze pad which canwithstandtheheatofyouralcohol
burner,and which will notendangeryour fingers while you are using it. To use
it, you placeitover the ringsupportand rest on it thecontaineryou wish to
heat.Youwillprobablywant several wire gauze pads.How toMakea Ring Support and a Clamp on an Upright Stand. Forthe
stand,obtaina pieceofwood 6 inches long, 4 inches wide and! inch thick.
Findthe center by drawingdiagonallines fromoppositecorners. Drill ai-inch
holethroughtheboardat thecentralpoint. Get a dowel sticki ofan inch in
diameterand 2 feet in length. With the help of the shopteacherin your school
or yourfatherat home, drillalternate! inch andi inch holes in the dowel
stick at intervalsof2 inches, beginning 4 inches from one end. You will be