First remove the tops or two tin cans. Make sure that you leave no sharp edges on the cans. Then punch a small hole in the center of each can's bottom. After that, cut a twenty-foot length of sturdy string Thread one end of the strng through the hole in the bottom of one can Repeat this procedure with the bottom of the second can Next tie strong knots in the ends of the string. The knots must prevent the sting from slipping out of the hole. Hold one of the tin cans to your ear and hand the other to a frHend. Keep a reasonable distance between you and you ffend. Now speak to one another. For better sending and receiving over your"telephones," rub the string with wax