Copper is frequently treated chemically to give it color.  Very pretty effects may be obtained by covering the tray with turpentine, then moving it about over a flame such as a bunsen burner until the turpentine burns off.  The copper will “take on” almost all the colors of a rainbow, and the effect will be most pleasing.

** Photograph of a Clown Face [181]

At first glance the accompanying photograph will appear as if the person photographed is wearing a false face or has his face painted like a clown.  On close observation you will notice that the face is made on the bald head of the person sitting behind the table.  The eyes, nose and mouth are cut from black paper and pasted on the bald spot.  The subject’s face is horizontal and resting upon his hands.

[Illustration:  A Bald Head Photographed]

** Finger Mathematics [181] By Charles C. Bradley

All machinists use mathematics.  Ask a machinist what would be the product of 9 times 8 and his ready reply would be 72, but change the figures a little and say 49 times 48 and the chances are that instead of replying at once he will have to figure it out with a pencil.  By using the following method it is just as easy to tell at a glance what 99 times 99 are as 9 times 9.  You will be able to multiply far beyond your most sanguine expectations.

In the first numbering, begin by holding your hands with the palms toward the body and make imaginary numbers on the thumbs and fingers as follows:  Thumbs, 6; first fingers, 7; second fingers, 8; third fingers, 9, and fourth fingers, 10.  Suppose you desire to multiply 8 by 9, put the eighth finger on one hand against the ninth finger of the other hand as shown.

[Illustration:  “8 Times 9”]

The two joined fingers and all the fingers above them (calling the thumbs fingers) are called the upper fingers and each has a value of ten, which tens are added.  All the fingers below the joined fingers are termed the lower fingers, and each of the lower fingers represents a unit value of one.  The sum of the units on one hand should be multiplied by the sum of the units on the other hand.  The total tens added to this last named sum will give the product desired.  Thus:  Referring to above picture or to your hands we find three tens on the left hand and four tens on the right, which would be 70.  We also find two units on the left hand and one on the right.  Two times one are two, and 70 plus 2 equals 72, or the product of 8 times 9.

Supposing 6 times 6 were the figures.  Put your thumbs together; there are no fingers above, so the two thumbs represent two tens or 20; below the thumbs are four units on each hand, which would be 16, and 20 plus 16 equals 36, or the product of 6 times 6.

[Illustration:  “6 Times 6” “10 Times 7”]

Supposing 10 times 7 is desired.  Put the little finger of the left hand against the first finger of the right hand.  At a glance you see seven tens or 70.  On the right hand you have three units and on the left nothing.  Three times nothing gives you nothing and 70 plus nothing is 70.