HOLLOWAY, TROmAS, 1748-1827: b. London; celebrated as an engraver. His chief work was in the illustration of Lavater's Essays on Physiognomy, for which he made about 700 plates. He also engraved some of Raphael's cartoons.
There are two classes of iron goods so-called—viz., cast-iron hollow-ware and wrought-iron hollow-ware. Both kinds include cooking and other vessels for domestic use, and comprise also some other articles, such as coffee-mills, which are molded and finished in a similar way. Wrought-iron hollowware is largely made by the process of stamping (q.v.), but a great deal is also made by the older way of joining pieces together. Vessels of this kind not intended, for cooking are generally coated with zinc, While those Odell are have usually a oating, of tin. Both metals are put on the iron by immersion. There is also a process in use for coating the surface with silicious enamel, which will be described presently. Since the introduction of these methods of protecting and beautifying the surface of iron, domestic vessels of this metal have greatly taken the place of those made from copper and brass.
Cast-iron hollow-ware is finished in three ways—some of it is enameled, some tinned, and some of it is left black, or untiuned; but there is comparatively little of the last DOW used. The process by which tinned hollow-ware is made was patented by Jonathan Taylor, a Birmingham workman, in 1779. It is conducted as follows: A vessel, such as a saucepan or goblet, is cast in a mold prepared in the ordinary way front an iron or a brass pattern. See Fon:mini The vessel is then annealed (q.v.), so as to soften the east-iron preparatory to turning, and such articles are then turned quite smooth on the inside, by means of a common lathe when they are circular, and by an oval lathe when they are oval like fish-pans, a workman holding and directing the tool in both cases. Self-acting lathes have been tried, but hitherto without any saving in the cost. The operation of tinning follows next, and is performed by the workman pouring small quantities of Melted tin on the inside of the vessel, which he rubs on with a ineee. of cork, gradually going over the whole surface. A little sal-ammoniac is thrown in during the process to make the tin adhere. Handles of malleable iron are then put upon suer! vessels as require them, and a final finish is given to•them by coating the outside with a black varnish which is dried in a stove. The covers of saucepans are made of tin-plate,
those for tea-kettles of cast-iron.
With respect to the enameling of caa hollow-ware, a patent was taken out for this as far back as 1799; but the process then introduced, in which the enamel contained lead and tin, was ultimately abandoned. The subsequent patent of Messrs. T. & C. Clark, of Wolverhampton, taken out in 1839, has been more successful. Their enamel is applied to the cast-iron in two coatings, one of which forms the body of the enamel, and the other the glaze, both being free from metallic oxides. It is especially desirable to avoid the oxide of lead, as it does not resist the action of acid substances in culinary operations. As iron, in common with most metals, differs from any vitreous enamel in the rate of its expansibility by heat, there is of course a difficulty in securing the per manent adhesion of the two substances, especially with such an article as a cooking vessel. In the case of cast-iron vessels, the difficulty has been practically overcome.
In England cast hollow-ware is made chiefly in the Midland hardware district, of which Birmingham and Wolverhampton are the centers. About 2,500 hands are employed, and the quantity of materials annually consumed is estimated at 12,000 tons of pig-iron, 1000 tons of wrought-iron, 177 tons of tin, and 23,000 tops of coke and coal. In Scotland there are also several Manufactories of tinned hollow-ware, that of the Carron company having long been famous. Wrought-iron hollow-ware is made princi pally in Birmingham and the surrounding district, and the number of hands employed upon it is probably nearly the same as for cast-iron goods of this kind.
With regard to the comparative merits of the different varieties of hollow-ware, there is no doubt that the kind made of enameled cast-iron is, on the whole, the best for cook ing purposes, although it is about one-fifth dearer than when merely tinned, and is, moreover, not liked by cooks for any but small-sized vessels, on account of its being somewhat heavy. Enameled wrought-iron cooking-vessels are much lighter to handle, but then upon them the enamel does not stand nearly so well, very probably because the comparatively rapid heating up of the thin iron of which they are made more rap idly destroys the adherence of the two substances. A great deal of cast-iron tinned hollow-ware is now made without being turned, an omission easily detected.