known as “Ba-en-pet,” or the celestial metal.[35] The only fragment of metal found in the great pyramid is a piece of plate-iron;[36] and if ancient iron objects are nowadays of exceptional rarity as compared with ancient bronze objects, it is because iron differs from bronze, inasmuch as it is not protected from destruction by its oxide.  Rust speedily devours it, and it needs a rare combination of favourable circumstances to preserve it intact.  If, however, it is quite certain that the Egyptians were acquainted with, and made use of, iron, it is no less certain that they were wholly unacquainted with steel.  This being the case, one asks how they can possibly have dealt at will upon the hardest rocks, even upon such as we ourselves hesitate to attack, namely, diorite, basalt, and the granite of Syene.  The manufacturers of antiquities who sculpture granite for the benefit of tourists, have found a simple solution of this problem.  They work with some twenty common iron chisels at hand, which after a very few turns are good for nothing.  When one is blunted, they take up another, and so on till the stock is exhausted.  Then they go to the forge, and put their tools into working order again.  The process is neither so long nor so difficult as might be supposed.  In the Gizeh Museum is a life-size head, produced from a block of black and red granite in less than a fortnight by one of the best forgers in Luxor.  I have no doubt that the ancient Egyptians worked in precisely the same way, and mastered the hardest stones by the use of iron.  Practice soon taught them methods by which their labour might be lightened, and their tools made to yield results as delicate and subtle as those which we achieve with our own.  As soon as the learner knew how to manage the point and the mallet, his master set him to copy a series of graduated models representing an animal in various stages of completion, or a part of the human body, or the whole human body, from the first rough sketch to the finished design (fig. 182).  Every year, these models are found in sufficient number to establish examples of progressive series.  Apart from isolated specimens which are picked up everywhere, the Gizeh collection contains a set of fifteen from Sakkarah, forty-one from Tanis, and a dozen from Thebes and Medinet Habu.  They were intended partly for the study of bas-reliefs, partly for the study of sculpture proper; and they reveal the method in use for both.[37]

[Illustration:  Fig. 182.—­Sculptor’s trial-piece, Eighteenth Dynasty.]

The Egyptians treated bas-relief in three ways:  either as a simple engraving executed by means of incised lines; or by cutting away the surface of the stone round the figure, and so causing it to stand out in relief upon the wall; or by sinking the design below the wall-surface and cutting it in relief at the bottom of the hollow.  The first method has the advantage of being expeditious, and the disadvantage of not being sufficiently decorative.  Rameses