Fig. 15.

From a point C as a centre, describe a circle A B equal to the large circumference; with the point F as a centre, the depth of the vessel, describe a circle D E equal to the small circumference ; then draw the lines G H and R S tangent to the circles A B and D E; from the point of intersection O as a centre, describe the arcs A C B and D F E; then A D E B will be the size of the vessel, and three such pieces will be an envelope for it, and A J B T F U the altitude: then by dividing the sector S 0 H into sections A B, D E, P Q, and W X, you will have a set of patterns for a pyramid cake ; and the sector A 0 B will bo one-third of an envelope for a cone.

In allowing for locks, you must draw the lines parallel to the radii, as represented in the diagram by dotted lines, which will bring the vessel true across the top and bottom.