I said that the inherent usefulness of the material of metal-work makes the destruction of its acquired form almost certain, if it comes into the possession of people either barbarous or careless of the work of a past time. Greek art is for us, in all its stages, a fragment only; in each of them it is necessary, in a somewhat visionary manner, to fill up empty spaces, and more or less make substitution; and of the finer work of the heroic age, thus dimly discerned as an actual thing, we had at least till recently almost nothing. Two plates of bronze, a few rusty nails, and certain rows of holes in the inner surface of the walls of the "treasury" of Mycenae, were the sole representatives of that favourite device of primitive Greek art, the lining of stone walls with burnished metal, of which the house of Alcinous in the Odyssey is the ideal picture, and the temple of Pallas of the Brazen House at Sparta, adorned in the interior with a coating of reliefs in metal, a later, historical example. Of the heroic or so-called Cyclopean architecture, that "treasury," [206] a building so imposing that Pausanias thought it worthy to rank with the Pyramids, is a sufficient illustration. Treasury, or tomb, or both (the selfish dead, perhaps, being supposed still to find enjoyment in the costly armour, goblets, and mirrors laid up there), this dome-shaped building, formed of concentric rings of stones gradually diminishing to a coping-stone at the top, may stand as the representative of some similar buildings in other parts of Greece, and of many others in a similar kind of architecture elsewhere, constructed of large many-sided blocks of stone, fitted carefully together without the aid of cement, and remaining in their places by reciprocal resistance. Characteristic of it is the general tendency to use vast blocks of stone for the jambs and lintels of doors, for instance, and in the construction of gable-shaped passages; two rows of such stones being made to rest against each other at an acute angle, within the thickness of the walls.