The joints were sometimes emphasized by grooves, but this ornament was used more frequently in Roman work. Until its introduction by the Romans the arch was rarely, if ever, employed, and the limit of inter-columniation was restricted by the necessity of finding stones of sufficient length to form the architraves. The roofs were generally of wood, covered with terra-cotta tiles or sheet metal, and left open at intervals for the admission of light. This is, however, a disputed point, as the wood, being perishable, has left no positive proofs of the method employed. It appears that an awning or sail was stretched over these openings when services were being held. It is probable that in many instances there was no light admitted, except that from the entrance door. The effect of a religious ceremony performed in the temples by the artificial light of torches, with the flickering fires from the tripods and votive stands reflected upon the ivory and gold of the statues, and the smoke wreathing weirdly above the heads of the assembled multitude, must have been infinitely more impressive than if lit by the colder light of day. The Greek colonists carried the principles of their architecture with them, leaving monuments of their genius wherever they established themselves. Of the temple of Diana, at Ephesus, nothing but a few fluted drums and scattered fragments remain to-day. It was the most magnificent temple of the Ionic order, erected with lavish expenditure, and decorated within with panels of cedar wood. It was burned and pillaged by the Persians. At Agrigentum, in Sicily, and Pæstum, in Southern Italy, there are several Doric temples of massive proportions. Of these the temples of Concord, Jupiter, and Neptune are the most notable. The columns are shorter and their capitals broader than the Athenian type, and in one instance there are two orders superposed, within the cella, to support the roof. The Greeks erected buildings in many parts of Southern Europe, in Asia Minor, and in Egypt, and in later times, even under the Roman conquest, they remained the masters of the arts, teaching their principles and supervising the erection of the monuments of Rome. The race was, indeed, peculiarly endowed with a genius for creating the beautiful, for though we have but scant information on the subject of Greek painting, we have preserved to us examples of sculpture which have never been surpassed or even equalled, and in architecture, though many more elaborate buildings have since been erected, nothing has ever been produced worthy of comparison with the harmonious proportions and majestic simplicity of the temples of Attica. V. ETRURIA AND ROME. Etruria was peopled, from remote ages, by the indigenous inhabitants, and by colonizing races from Asia and Greece.