The irons are made with various kinds of faces, some are perfectly flat, others with convex sweeps or curves, these are called “grecian” irons, and are intended to be used in recessed curves of crown or brim, which curves are known as “grecians,” but the skilful operative can adapt the curved sides of a flat-faced box iron to most of the concave places, so that except for extreme undulations, no recourse to the curved faced iron is necessary. There are many modifications of these general rules and methods, and it may be necessary in certain cases, such as the ironing of braids stiffened with _media_ other than gelatine or water soluble materials, to employ other methods, but they are generally peculiar to the plait used and of a purely ephemeral nature. In some factories box irons are used, heated by patent fuel, others are warmed by gas and electricity, but the general convenience of the fire-heated pad causes the old fashioned iron to retain an almost universal supremacy. In work it is just as convenient as any other, and in cost it must of necessity be lower, for every factory must have fire for steam production and general warmth, and the coke burning furnaces in use in the smaller factories are usually constructed to achieve these two objects, and at the same time heat the blocker’s pads. In the larger establishments steam for heating and working is generally raised in separate adequately large boilers, with a specially constructed and economical furnace for pad heating. This is made with a shallow bed, a broad iron lip, on which pads can be changed, and a guillotine-like construction in front, with a “blower” which can be made to rise or fall, as occasion may demand for the regulation of the draught. FOOTNOTE: [1] This doubtless gave the name to the operation of shaping. CHAPTER XII BLOCKING BY MACHINE