There are a great number of articles and parts of articles whose patterns can be developed as some portion of a cone surface. To explain the method that is followed in setting out patterns for this class of work, it will perhaps be as well to first go over the development of the surface of a of, and thus determine the shape of pattern that would exactly envelop the cut cone. This will be carried out by first describing a semicircle on the cone base, and dividing it into six equal parts; running lines down perpendicular to the base from each division point, and then joining up to the apex of cone. From the points where the radial lines intersect 0 A and D B, perpendiculars to the axis are drawn to the outside line of the cone; thus the true lengths of all the lines are projected on to the outside of cone, and can be measured off as required.