Place the paper so that the long edges are parallel with the front of desk; find the center of paper; with this point as a center draw a four-inch circle, and a four and one-half inch circle; place ruler in position to draw the horizontal diameters, and draw a radius of inner circle to the right; in line with diameters and two inches to the left of outer circle place a point, which shall be the center of a one and one-half inch circle; draw the circle.

Cut out a circular plinth of card-board equal to the last circle; place a point on card-board on the outer edge of circle; place the plinth in a vertical position so that the last point shall rest on the right end of radius of inner circle; roll the plinth upward along the circumference of the inner circle until the point in plinth again rests upon the circumference of inner circle; join this point in the circumference with the center.

Construct a one-fourth inch margin on the left side of this segment; construct isosceles triangles between the circumferences as in the cylinder.

Transfer to a scale of one to two. Cut, crease, fold and glue.