In the frusta of the columns, the stones are thicker; one in the Parthenon being 3 feet 7.8 inches in thickness; but probably that part of the quarry which would furnish blocks of such a thickness, did not afford them of considerable length. The architrave of the Parthenon is 5 feet 9 inches wide, and is got out in three thicknesses, probably on account of the difficulty of procuring pieces 14 feet long, and 2 feet 10 inches and a half thick, which would have been required, had it been constructed, as is more usually the case, in two blocks. In the frieze, there was not the same necessity that the work should be perfectly solid, and accordingly only two beds were used, leaving a vacancy of about 10 inches in the middle. Thus this peculiarity which Clarke _discovered_ to be owing to the dishonesty of the workmen, and Wilkins considers a proof of great science and foresight, may with greater probability be attributed to the nature of the quarry. The ceiling of the pronaos and posticum was formed by marble joists supporting slabs of the same material, which contained the lacunariæ; but in the lateral peristyle, these slabs were laid from the wall to the external epistylium, without the intervention of joists. You may see here in several places marks of ancient ornamental painting, and in some instances of painting of two different styles and dates, one of which has been over the other. In parts sheltered from the weather, there are even indications of painting on the outside cornice. There are some very curious contrivances in the construction of the cornice, at the south-west angle, with which I will not at present trouble you, as I do not think them very good.