Iron nails with ornamented heads and decorative door-knockers are other objects which reveal the influence of Mohammedan Spain. A number of artistic Spanish nails are in the South Kensington Museum. "Some doors," says Riaño, "still exist at the Alhambra, Granada, covered with enormous heads of nails of a half-spherical form with embossed pattern. These same nails are constantly to be found on old Spanish houses, to which are added in the angles pieces of iron of a most artistic order" (Pl. xix.A). In the same city, though not precisely in the Alhambra, I have seen upon the doors of private houses nails of a decorative kind which appear to consist of a single piece, but which are really formed of two--an ornamental boss perforated through its centre, and the nail proper, which fastens through it to the woodwork of the door behind. Thus, when the nail is hammered tight upon the boss, the effect is naturally that of a single piece of metal. Similar nails are on the door of Tavera's hospital at Toledo. [Illustration: XIX_a_ DECORATIVE NAIL-HEADS (_Convent of San Antonio, Toledo_)] The _Ordenanzas_ of Granada tell us minutely of the nails which were produced there in the sixteenth century. They were denominated _cabriales_, _costaneros_, _palmares_, _bolayques_, _vizcainos_, sabetinos, and _moriscos_; of all of which I can only find that the _cabriales_ and _costaneros_ were used for beams and rafters, and the _moriscos_ for fixing horse-shoes. In Spain the custom of fastening down the decorative coverings of chairs or benches dates from comparatively late; and it was probably with this innovation that iron-workers began to exercise their ingenuity upon the heads of nails. Towards the close of the Middle Ages the city of Segovia was celebrated for her locks and keys, her knockers, and her _rejas_. In 1892, collections of iron objects, chiefly manufactured in this town, were shown by the duke of Segovia, Don Nicolás Duque, and Don Adolfo Herrera at the Exposición Histórico-Europea of Madrid. Segovia still preserves an old door covered with extraordinary iron spikes, that once belonged to the castle of Pedraza; many curious balconies, such as that in a first floor of the Calle del Carmen; and the grilles--proceeding from the old cathedral--of the chapel of the Cristo del Consuelo and the chapel of the Piedad. Another interesting collection of early decorative Spanish iron, belonging to the well-known painter, Señor Rusiñol, is kept at the town of Sitjes, in Cataluña. The late Marquis of Arcicollar possessed a number of specimens of Spanish manufactured iron of the later Middle Ages, such as boxes, candelabra, locks, nails, door-knockers, _braseros_, and a rare and curious iron desk (fourteenth century), with leather fittings.